The delivery efficiency of complex weapon equipment directly affects the transformation of national defense combat effectiveness. In order to improve the delivery efficiency, based on the multi-task characteristics of the complex weapon equipment delivery problem, we establish the delivery chain incentive contract model under accountability mechanism to explore the impact of accountability mechanism, equity, risk, dependence and other factors on incentive contract under information asymmetry and information asymmetry. It shows that fair factors have obvious incentive effects on the departments' effort level and the agents invest more efforts on relatively important and low-cost tasks. The comprehensive technical level, the fair preferences, the dependency coefficient have an impact on the optimal incentive contract, and the optimal incentive contract is affected by its risk type and degree. The accountability mechanisms can improve the overall effort level and the proportion of the income in certain conditions. The research conclusion can provide theoretical support for complex weapon equipment delivery.