A pyrolysis experiment of gas generation of source rock sampling from Qaidam Basin was carried out with a high pressure and closed gold tube reaction system. The results show that activation energy of CH₄ ranges from 49 kcal/mol to 67 kcal/mol with two peaks of 57 kcal/mol and 66 kcal/mol in a diagram of activation energy distribution if its frequency factor of 1×10¹²/s is assumed. Based on gas generation history simulated by kinetics software and two artificial simulation wells at the centre of Saishenteng depression and its slope, it is suggested that the Lower Jurassic source rock in the central Saishiteng depression and its slope entered the gas generation threshold at 29.8 Ma (R_O is 0.67%) and 23.8Ma( R_O is 0.87%), respectively.