Under the circumstances of uncertain fluctuation of market demand, the degree of matching between production capacity and customers demand can affect the cost, the efficiency and the profits of an enterprise. Choosing the appropriate production capacity level is an important task for decision makers. The paper analyzes the characters of the short-term demand variation, the matching between the capacity and the demand, and its influence on the enterprise. Supposing the short-term demand varies seasonally, and the objective is minimum the loss of mismatch between the production capacity and market demand.Then,short-term production capacity decision model has been developed.Based on the model, this paper has probed into the mismatching loss of three strategies: fixed capacity strategy, subsection adjustment capacity strategy and dynamic adjustment capacity strategy,and an optimal capacity strategy is provided. By fixing the capacity-demand mismatching loss and changing the capacity adjustment rate, this paper also studies the sensitivity of the capacity strategy. The result shows that, firstly, as the capacity adjustment rate is less than a certain numerical value, the dynamic adjustment capacity is the optimal choice; secondly, as the capacity adjustment rate exceeds a certain numerical value, the optimal one is fixed capacity strategy; finally, as the rate falls in some specific area, the optimal one is subsection adjustment capacity strategy. One practical example is provided to prove the model's validity.