Abstract: Quality risk management of out sourced logistics is studied from a fourth party logistics perspective. Based on principal-agent theory and contract design knowledge and considering the third party logistics risk averse and private information,the optimal contract design under different scenarios is studied. The optimal contract parameters for fourth party logistics and the optimal effort level for third party logistics are then obtained. The results reveal that the derived contract can induce the third party to work hard and effectively reduce the logistics quality risk. Meanwhile,the study shows that both risk averse and asymmetric information of the third party logistics will increase the fourth party logistics quality risk. The results of computational studies reveal that the effect of risk averse information on the fourth party logistics quality risk is usually more significant than that of asymmetric information.