In order to improve the successful probability of equipment research and development project, new risk evaluation model should be provided. This paper expanded the dimension of project risk, and ameliorated the extenics method to construct the risk evaluation model. In this method, used the plus correlative function value between risk state to risk grading interval to multiply the middle value of risk grading interval to calculate the risk degree of single risk index in multi-dimensional risk measure index, then integrated the geometrical mean and arithmetic mean of single risk index to count the synthetical risk degree of equipment research and development project. Which provide new technique for equipment project risk evaluation.