To effectively reduce or hedge the development risk of weapon equipment for smooth project progress, a comprehensive assessment method based on SPA(set pair analysis) theory and LS-SVM (least square support vector machine) method was proposed for weapon equipment development. Firstly, according to the specific characteristics of weapon equipment development, the weapon equipment development risk assessment index system was established. Secondly, on the basis of this, the concept of connection degree and set pair in SPA theory was introduced to construct the training samples and test samples. Finally, through the obtained samples, LSSVM was trained and tested to get the assessment model and to produce the assessment result. An example analysis shows that the proposed method has many advantages in simple implement, combining the qualitative analysis and the quantitative analysis, easy understanding. The assessment results are more close to the actual development. It has important practical significance to improve the risk management and decisionmaking level of weapon equipment development project.