The validation of modern military simulation relies heavily on the opinions of military experts, and it makes the validation task exhaustive and time-consuming. The knowledgebased methods can be applied for these problems. There are three kinds of knowledge sets in military simulation validation, namely, domain knowledge, inference knowledge and validation task knowledge. By analyzing the context of these knowledge, three types of knowledge models are developed. Based on these knowledge models, the implement of knowledge-based system is detailed. However, this validation system can be practical for the validation of military simulation by enriching the knowledge base.