The total minimum commitment contract with periodic order constraints, multiple suppliers and stochastic and non-stationary demands was addressed. A stochastic multidimensional dynamic programming model was developed to minimize the expected value of the sum of procurement, inventory and shortage cost for the purchaser in the planning horizon. At first, the optimal procurement policy in single period was obtained according to the newsboy model after the order constraints and multiple suppliers were considered. Then the heuristic policy for multi-period procurement was derived from the one in single period. An illustrative example was presented and some simulations were made to show the effect of demand mean square deviation, unit shortage cost, periodic order constraint and total minimum commitment on the optimal policy and the minimum cost. This work extends the total minimum contract to the stochastic and non-stationary demands and multiple suppliers setting and can provide decision-making support to the procurement of enterprises in supply chains.