Based on core observation, testing and logging data of Chang 6 reservoir at H area in Ansai Oilfield, the heterogeneities of Chang 6 ^{1- 2}, Chang 6 ^2-1 and Chang 6 ^{2- 2} sublayers are studied, and the effect and control action of the heterogeneities on oil-bearing property are analyzed. The result shows that there are strong interlayer heterogeneity and strong in-layer heterogeneity, but weak planar heterogeneity of Chang 6 reservoir in the study area. The rhythmicity of grain size in vertical direction and the stratification features are important factors for the hydrocarbon distribution. The in-layer permeability heterogeneity and the difference of stratification coefficient between each sublayer play a weak role in controlling the hydrocarbon distribution. The difference of sand density also controls the hydrocarbon distribution, but not the main controlling factor. The oil-bearing properties are mainly controlled by the sand body distribution and reservoir properties, and the microscopic heterogeneity in pore structure controls the full degree of hydrocarbon entering into the reservoirs.