Due to the rapid growth of the IT industry as well as the high failure rate of software development projects, it is highly desirable to develop a qualitative approach for dealing with uncertainties in the software development process. In order to manage risk and uncertainty, a software project uncertainty management approach based on a generalized stochastic Petri net is proposed. It consists of two main components: model building based on a Petri net and a Markov process algorithm. The technique is presented with an example. Finally, the proposed model is demonstrated with a real-world case.