Abstract: Based on study method of organic lithology, Samples from an evolutional sequence ofcarbonates in northern China were studied in detail on the Principle of simplicity, practicality and systematization. The organic matters in carbonates were classified into 3 types:allogenic, autogenic and secondary ones according to their characters, origin, sedimentation and msturation. Each kind of organic matters was subdivided into maceral suite, maceral and sub-maceral.