Secondary clay minerals formed by basalt alteration are often filled in pores and fractures, resulting in the reduction of reservoir space and reservoir capability and bad reservoir effectiveness. The purpose of this paper is to eliminate the effect of alteration and make the storage evaluation conform to the production capacity. The authors classified the alteration into four grades, i.e., mild alteration, moderate alteration, severe alteration and argillization, then comprehensively analyzed the effectiveness of pores according to microscope image features of melaphyre's pores and the influence of alteration on conventional, imaging and NMR logging data. As the fractures make valuable contributions to reservoir capability of basalt, the fractures effectiveness and reservoir integral permeability were analyzed according to the DSI logging based on the influence of clay minerals on fractures. Finally, comprehensive evaluation of reservoir capability was carried out in combination with reservoir physical parameters and effectiveness analysis of pores and fractures,and the reservoirs were classified into ClassⅠ, Ⅱ and Ⅲ in accord with the production capacities.