In order to deeply understand the relationship between the microstructural characteristics of volcanic reservoirs and the lithology of volcanic rocks, it provides important theoretical significance for the effective development of volcanic reservoir oil and gas fields. The microscopic characteristics of the volcanic reservoirs of the Yingcheng Formation in the Songliao Basin were analyzed by means of rock section determination, pore structure parameters analysis and casting thin section analysis. The results show that the target layer has low porosity and permeability, and the volcanic pore structure of different lithologies is different. Volcanic lava generally develops original gas pores, phenocryst dissolved pores, matrix dissolved pores, and tectoclase, while volcanic clastic rocks generally have developmental dissolution pores as the main feature. The micro-heterogeneity of volcanic reservoirs is generally strong, and the development of tectonic fractures is an important factor in changing the reservoir performance of volcanic rocks.