Thermal cracking data from marine and lacustrine oils were provided by using gold tube and different gas generation kinetic parameters in this paper. Based on the comparative studies of gas generation characteristics from different oils, influence of heating rates and temperatures on oil cracking process, the following results can be proposed: The threshold temperature and deadline temperature for gas generation from marine and lacustrine oils in China are usually similar, but different with other oils from abroad; oil cracking environments (inside the source rock or outside the source rock) and hydrocarbon expulsion efficiency have important impact on the oil cracking process; temperature is the major controlling factor on oil cracking process and this process usually accomplish in 10Ma when the environment temperature is higher than 180℃, and the oil deadline temperature is higher than 200℃ in most cases. We believed that the data and conclusions provided in the paper would be beneficial to basin modelling and oil reservoir prospecting.