The quantitative evaluation criterion for the conglomerate reservoir was established on the basis of studying the micro heterogeneity characteristics of reservoir, in order to understand micro heterogeneity and quantitatively evaluate the degree of densification for the conglomerate reservoir of the Upper Permain Wutonggou Formation int DN8 area of the Dongdaohaizi sag, eastern Junggar basin, based on identification of blue epoxy resin-impregnated thin sections, analysis of scanning electron microscope (SEM), X-ray diffraction (XRD) of minerals, high-pressure capillary pressure, combined with previous research results. The results show that the micro heterogeneity of reservoir mainly includes petrological heterogeneity, pore throat heterogeneity and fracture heterogeneity. In petrological heterogeneity, the rock structural heterogeneity caused by the difference of rock structural maturity restricts the initial physical property of reservoir. The degree of reservoir densification is affected by types and contents of gravels, cuttings in synsedimentary interstitial matterial and cements after compaction and cementation. The degree of current reservoir densification is affected by the pore throat heterogeneity and fracture heterogeneity, which caused by the difference of diagenesis-pore evolution process after dissolution and the fracture development density. The diagenetic comprehensive parameter (DCP) and formation brittleness index (FBI) are thus put forward to characterize densification degree of the reservoir, which can be divided into three grades. The DCP is greater than 4.0 and the FBI is greater than 0.8 in the first grade of densification. The DCP is between 3.0-4.0 and the FBI is between 0.3-0.8 in the second grade of densification, and the DCP is less than 3.0 and the FBI is less than 0.3 in the third grade of densification. The tight reservoir of the first grade is with the best pore throat structure and the highest quality, thus of the weakest micro heterogeneity, which is the favorable conglomerate reservoir in the study area.