Abstract: The volcanic rock oil reservoir of the third member in Kongdian Formation has become the new bright spot for oil and gas exploration in Weibei sag.The reservoir property is the key factors of hydrocarbon accumulation abundance of the reservoir.Through core observation,slice identification,combined with analysis of testing data,logging and seismic data,the main control factors on the volcanic reservoir of the third member in Kongdian Formation has been analyzed.It is believed that the physical property of reservoir is influenced mainly by the volcanic facies,eluviations and structures.The volcanic facies controlled the band of gas pore,being the material basis for the evolution of the space.The tectonism formed fractures,and it can improve the connectivity of primary pores.The weathering and leaching can form eluvial horizon which is beneficial to hydrocarbon migration and accumulation.Through analysis of the three control factors on the reservoir,a triangle volcanic reservoir evaluation method has been established.The volcanic rock reservoirs in the study area are divided into four categories.The study results are significance in predicting volcanic reservoir in the area,and the classification evaluation method is also significant to volcanic reservoir evaluation in the similar areas.