Scheduling for chemical batch process has been an active area of research over the past decade. The uncertainties of the process, which expand the scope and complexity, make the formulation and solution of the stochastic scheduling very intractable. A novel mathematical formulation which combined statistical probability theory with the deterministic scheduling was proposed. And the discretion of the stochastic variables transforms the stochastic programming problem into a probability statistics of deterministic scheduling, which overcomes the hardship. An example of stochastic scheduling of batch process with uncertain processing time of uniform distribution indicated that the relationship between the deadline and the probability of optimal scheduling, and the distribution of the makespan of the optimal scheduling with process time uncertainty was also studied. The proposed formation can also be used for the stochastic scheduling of batch process with uncertainty of market demand, equipment availability and so on.