According to the disadvantages of design method of traditional riser, this article introduces the design method of riser which is based on the computer aided engineering technology , the casting process of exothermic and insulating riser for steel casting of gear ring seat of excavator was simulated by Anycasting software . the riser modulus was directly calculated according to the solidification time of the casting by the simulation, Meanwhile its volume and quantity could be confirmed by the feeding liquid volume method. The result shows that the feeding effect of the exothermic and insulating riser design is perfect,The method can ensure no shrinkage defect in the casting, and also improve the technological yield ,thus it is validated that the technique is feasible.