Abstract: In this paper, the pyrolysis kinetics of the hydrocarbon formation in the source rock was studied by using modified Rock-Eval Apparatus with constant heating up rates incressed (at 2, 5, 10, 15, 20℃/min). The immature soure rock samples were taken from Dongpu Depression at a burial depth of 1801 m. The different temperatures at maximum reaction rate (T_max) were obtained from the experiments with different heating up rates. According to these T_max, by regression with a model of maximum reaction rate equa-tion apparent activation energy and pre-exponential factor of this source rock sample were calculated, as 199.6KJ/mol and 2.803×10¹³sec^-1 respecti- vely. Based on these two kinetic parameters, and the rate of subsidence(0.26mm/y)and the geothermal gradient(0.03℃/min)of Donapu Depression, the rate of hydrocarbon formation in the source rocks at different depth were calculated. For example, at a depth of 2768m, the rate of hydrocarbon formation is 0.05(upper threshold); at a depth of 3571m, thi:rate is 0.95(lower threshold). The variation of hydrocarbon generation rate with the burial depth was also obtained. The variation of hydrocarbon generation rate with the burial depth was also obtained. The burial depth was about 3337m where maximum reaction rate occured(hydrocarbon formation peak). The results calculated matches satisfactorily with the actual situation. The characteristics and the reliability of the model were discussed. It is shown that the maximum reaction rate model is a simple and applicable one, and the Rock-Eval Apparatus can be well used for pyrolysis kinetic study of source rocks. The results used in the calculation of hydrocarbon formation fractionof source rock at different burial depth is useful in the evaluation of oil and gas resources and in petroleum exploration as well.