The paper mainly studies the optimization and coordination of the secondary logistics service supply chain considering the reliability participation. The research shows that when the second-class logistics service supply chain composed of the fourth-party logistics integrator and the third-party logistics provider is studied, the reliability of the provider is added, and the principal-agent theory is used to establish an optimization contract model with reliability participation, it will be beneficial to improve the optimal logistics capacity of the supply chain and increase the profit of the integrator and provider. The reliability of the provider is negatively related to the expected profit of the provider and the logistics service supply chain, which is positively related to the expected profit of the supplier.