The Shahezi Formation in the Anda-Songzhan block is a typical tight sandstone reservoir. Diagenesis is the main influencing factor for the densification of the Shahezi Formation reservoir. Research on the types of reservoir space, diagenesis and the relationship between diagenesis and pore evolution in the Shahezi Formation reservoir is conducted by combining experimental analysis methods such as ordinary thin sections, cast thin sections, X-ray diffraction whole rock, scanning electron microscopy and mercury intrusion. The results indicate that there are three types of pores in the tight reservoir of the Anda-Songzhan block: primary pores, secondary pores and microcracks. Secondary pores are the main pore type and conglomerate microcracks are more developed. The types of throat are Sheet-like, curved Sheet-like and bundle shaped. The types of reservoir diagenesis comprise compaction, cementation, recrystallization, metasomatism, dissolution and tectonic fracturing. The destructive effects on the reservoir include compaction and cementation. The metasomatism has little effect on the reservoir. The constructive effects on reservoirs include dissolution, recrystallization and structural fracturing. The diagenetic stages of the sand conglomerate reservoir in the Shahezi Formation can be divided into early diagenetic stage, middle diagenetic stage and late diagenetic stage. The compaction process runs through various stages of diagenesis, causing the basic disappearance of primary pores and ultimately transforming the throat type into Sheet-like and curved Sheet-like throats. The cementation process mainly occurs in the middle and late diagenesis stages A, further occupying the intergranular pores and forming intergranular shrinkage pores. The recrystallization process initiates at middle diagenesis stage A and becomes more pronounced with increasing burial depth, leading to the formation of intergranular pores and tubular throats. The dissolution process primarily takes place in the middle diagenetic stage B, with some minor dissolution also occurring in the late diagenetic stage A, forming the secondary pores.