The lithology of reef flat reservoir of Upper Ordovician in Tazhong No.1 slope break is mainly composed of carbonate. Because the reservoir space is various and complicated in the quantitative evaluation of well logging, there are a series of difficulties to evaluate carbonate with well logging data. The well logging data combining with core, experiment and well test are applied to divide the space and types of reservoirs, establish different response characteristics and models for different types of reservoirs, and build the division criterion of reef flat reservoir. According to the relationships between porosity and penetration of different types of reservoirs, the interpretation charts and criteria for different classified reef flat reservoirs are established, which provide dependable criteria for the reservoir evaluation and the choice of interval in well testing.