In the incentive mechanism of the logistics service supply chain, integrators neglect to encourage providers to improve their service capabilities, which is an important reason for poor incentive effects. In order to solve this problem, considering the multi-agent competitive relationship, the learning effect is taken as a factor affecting the improvement of the provider's ability, and constructing a principal-agent model to study the impact of learning effects on the incentive mechanism of logistics service supply chains. The results show that the learning effect can urge providers to take more risks, improve their efforts level and service capabilities, and increase the integrator's expected income; the greater the degree of competition between providers, the more obvious the incentive effect brought by the learning effect.