The insurance agents can do business actively at present under the promptings of the incentive mechanism, however the high commission in the early time would bring about short-term behavior inevitabl. In a sense, it is necessary to extend the term, but thus could not bring out sufficient incentive. The long-term model of the incentive contracts of insurance agents with the method of modern incentive theory analyzes the relationship between the incentive and the length of the term and the conclusion which is drawn from this model can be helpful in the mechanism design of insurance sale contracts in the near future.