Abstract: In the environment of triple random fluctuation of wholesale price, exchange rate and demand, the joint decision of cross-border procurement and pricing is considered. In this paper, the randomness of wholesale price and exchange rate is characterized by stochastic process, and the statistical regularity of the two is incorporated into the theoretical framework of the decision model with stochastic demand, then the joint decision-making model of transnational procurement and pricing and its reliability evaluation mechanism are given. The relevant conclusions of the model show that: firstly, the optimal strategy of different cycles is affected by the interaction between wholesale price and exchange rate fluctuation. When the overlapping effect of wholesale price and exchange rate fluctuation has a downward trend, the optimal strategy adopted by the seller is to increase a certain amount of purchase to achieve the expected profit target of the system. Secondly, when the statistical structure of wholesale price and exchange rate is irreducible traversal Markov chain, the downside risk of stochastic system has good stability. Thirdly,the decision-maker can propose a penetrating evaluation mechanism of targeted cost interval to depict the cost increase characteristics and change trend of the random system, so as to solve the problem of optimal supplier selection， thus achieve the operational goal of risk avoidance.

Key words: multiple random factor; global sourcing; dynamic pricing; risk evaluation mechanism