Abstract: This paper introduced in detarl the method and principle of calculating hydrocarbon- forming quantity and hydrocarbon -excluding quantity by method of basin simulation and its softwares structure, and described preparations of parameters in basin simulation and results gained by simulation,which regarded dividing structural developmental history of Junggar Basin into three stages as correct, determined the thermal evolution stages of a" the source rocks and showed that the main source rocks are Fengcheng and low Wuerhe groups. The simulation solved the unbalanced problem presented for longtime between hydrocarbon- forming quantity in Mahu Depression and geological reserves,hydrocarbon- vanishing quantity in it and its circumference. And displayed the distribution of resources in simulated region. And provided scientific bases for exploration arrangement,