In order to effectively evaluate DDoS attack and defense behavior to defend against DDoS attacks, this study first analyzed the current research status of DDoS attack and defense evaluation, and then established DDoS attack and defense behavior confrontation net based on stochastic Petri net. The attack and defense steady state probability is used as the basis for the evaluation of attack and defense behavior. The solution of attack and defense game strategy based on the attack and defense game theory were proposed. In the end, we carried out the stability analysis of the DDoS attack and defense behavior confrontation net, and comprehensively considered the factors of attack and defense behavior gain and attack and defense behavior intensity to simulate and evaluate. The evaluation results show that the method is more reasonable and pertinent.