How to choose the best investment ratio of assets is the most important issue in the use of insurance funds.This paper employs the investment proportion model considering underwriting risk.The result from empirical estimation shows that the optimal investment ratio of insurance funds in bank deposit,treasury bond investment,financial bond investment,enterprise bond investment,securities investment funds and stocks is 9.23％，11.06％，12.22％，14.02％，29.34%，24.13％ respectively.The comparative analysis shows that use of insurance funds in China is gradually optimized and the ratio of investment is becoming more and more reasonable.However,compared with the optimal investment ratio,the ratio of bank deposit should be reduced and at the same time the ratio of securities investment funds and stocks should be gradually increased.