Depending on the data of high-resolution image log and the geological calibration of dolostone core samples from Well Kuang-2 in the northwest of Sichuan Basin,a typical profile of Lower Permian Qixia dolostone reservoir structure is characterized,by which five types of dolostone and limestone and four types of effective reservoir spaces can be identified.It is shown that multiple pore system develops in Qixia dolostone,in which solution pores and intercrystal pores are contributive commonly.The solution pores appear as layers or quasi-layers in massive medium-and coarse-graine d dolostone (in one strata unit with the thickness of 39.5m) and the intercrystal pores exist in porphyritic medium- and coarse-grained dolostone (in 4 strata units with the average thickness of 1.1m).Other two types of reservoir space,including solution-enlarging fractures and late structural fractures are less contributive.The massive dolostone develops in the HST of the 3rd sequence but the porphyritic dolostone only develops in the upper part of the upward-shallowing cycle of the 4th sequence.