Intraocular pressure (IOP) is an important indicator for diagnosing glaucoma, and it is an essential parameter to show the intraocular status. Researches show that when intraocular pressure increases 1 mmHg, the risk of getting glaucoma increases by 10%. It is not directly measureable due to its inner attribute; hence, the tonometers exist now all utilize the outer response of the cornea to obtain IOP. The measurement of IOP is done in vivo, and its magnitude is 10 mmHg, which require the tonometer to have a resolution of 1‰ atm. Goldmann applanation tonometer (GAT) is considered as a “gold standard” in IOP measurement, however, it bases on the assumption of the cancelation of corneal reaction force and surface tension of tears. The assumption highly depends on the properties of cornea (elastic modulus) and tears, which are difficult to be determined. This assumption would cause the IOP measured to be lower than the actual situation, with a magnitude that could reach the critical pressure to cause the damage of optic nerve, which will greatly jeopardize the diagnose and treatment of glaucoma. In view of the above mechanical defects of "gold standard" tonometer, hydrogel/silicon hydrogel materials (used for contact lenses) with similar properties to cornea were used to prepare artificial cornea with similar shape to real cornea to simulate the corneal flattening process of Goldmann tonometer. At the same time, the elastic modulus of the hydrogel material was determined by uniaxial tensile sample with the same water content as the artificial cornea. The relationship between the resultant force of the indenter and the descending displacement of the indenter and the liquid film spreading radius was tested by micro-force material testing machine, and the interaction between the cornea and the liquid film on the indenter was determined. Establish a method to separate the effect of cornea and liquid film on IOP and determine the depth/load/contact area corresponding to the decoupling effect. At the same time, the whole pig eyeball was flattened to confirm the reliability of the test law. The main research content of this paper can be divided into two aspects: to investigate the mechanical response of solid (cornea) and liquid (tears) film and the principle of decoupling the effect of cornea and liquid film on IOP. (1) With the results of simulation and experiment, the influences of the resultant force of the indenter, the corneal reaction force, the surface tension of liquid film, and the force generated by the intraocular pressure with the descending displacement of the indenter and the liquid film spreading radius during the flattening experiment were determined. The result is as follows: (a) The resultant force of the indenter, W, increases with the increase of liquid film spreading radius, a. With the same liquid film spreading radius, a, the cornea with larger thickness, smaller curvature radius or higher elastic modulus has larger resultant force, W, and the corresponding measured value of intraocular pressure IOPG is larger; (b) The relationship between resultant force of the indenter, W, surface tension of liquid film, Ft, corneal reaction force, Fc, and force generated by intraocular pressure, FIOP, during the flattening experiment can be expressed as follows: W + Ft = FIOP + Fc = IOP×𝜋×(𝑎−𝑎0)2+Fc; (c) The surface tension of liquid film, Ft, can be regarded as a constant value in the process of intraocular pressure measurement, and the magnitude is 1 mN; (d) The corneal reaction force, Fc, showed a good linear relationship with the flattening radius, ac, within the thickness range of cornea, that is, Fc~K1× ac. The coefficient, K1, was related to corneal thickness, t, corneal radius of curvature, R, and corneal elastic modulus, E, K1=2Et2/R. (2) The relationship and difference between corneal reaction force, surface tension of liquid film, depth and liquid film spreading area were analyzed, and the inverse solution governing equation was established. The results are as follows: (a) According to the expression of the mechanical quantity existing in the process of the flattening experiment, by setting three specific liquid film spreading radius a1, a2 and a3 as the reference, the ternary first-order equations can be obtained. By solving the equations, the intraocular pressure IOP and the elastic modulus E can be obtained. (b) According to the results of the pig eyeball flattening experiment, the range of elastic modulus E of the pig cornea was 7 to 40 kPa.