Abstract: Microgel flooding is another new and good tertiary oil recovery technology following polymer flooding and is being popularized and applied in many oilfields. As the key of plan design, numerical simulation technology is also developing progressively and the software is also perfecting and upgrading progressively. Since microgel flooding involves complex physical and chemical changes, how to a-chieve physical and chemical parameters become very important during numerical simulation. The meanings of the main physical and chemical parameters are analyzed and the methods for solving these parameters are presented. They can be used to guide numerical simulation of microgel flooding.