A wide range of sediments formed in various sedimentary environments, including coals, carbargillites, shale and mudstones collected throughout China, have been studied by laboratory pyrolysis. The results show that the vitrinite reflectivity (Ro) values of these samples generally increase with an increase of pyrolysis temperature. However, the degree of increase in vitrinite reflectance is different from sample to sample. The corresponding pyrolysing temperatures for the peak generation of liquid hydrocarbons also reveal the apparent fluctuation among the samples. These variations are largely controlled by the properties of the source rock and types of organic matter, which are closely related to the primary sedimentary environments. Therefore, the sedimentary environment, age and the buried history should be considered when Ro and hydrocarbon yield of source rock are used to assess the source rock and basin.