This article through the electronic transaction management system to obtain the sales data of merchandise, through by clustering analysis method and statistical goodness of fit methods to predict the distribution of demand. The length of lead time and the different stochastic demand distributions will influence the reorder point. Therefore, we build up an inventory decision model of general merchandise under given lead time, and using optimization techniques to find out the optimal ordering quantity and reorder point, through numerical examples to verify the feasibility and correctness of the proposed model. Finally, two specific conclusions are taken for future studies and practical applications.