The invention discloses a preparation method of reduced graphene oxide-polyimide heat treated foam. The method particularly comprises the following steps: crosslinking graphene oxide and polyimide foam, performing chemical reduction, and performing physical reduction. The method has the advantages that the polyimide foam is taken as a template, chemical and physical double reduction of the graphene oxide is skillfully realized, the double reduction of the graphene oxide improves the conductivity of graphene foam, the sensitivity of the graphene foam to pressure is improved, weak pressure can be measured, and the problems in the prior art that the graphene foam is low in mechanical property, the preparation technology is complex, the cost is high, the shape, density and pore size of the graphene foam are difficult to control.