In view of the problems that traditional method is single and limited in Beyond-Visual-Range (BVR) air combat situation assessment, this paper introduces a multi-source information fusion evaluation framework based on D-S evidence theory. Taking assessment outputs of three distinct methods as independent evidence bodies and subsequently processing through D-S evidence theory for deep-level fusion, a comprehensive estimation of air combat situations is obtained. The fused evaluation results show that the characterization capability of key features for air combat situations is obviously enhanced compared to the individual methods. The fusion approach establishes a more rational and robust quantitative foundation for command decision-making in air combat operations, effectively contributing to the improvement of both scientific rigor and timeliness in air combat decision-making processes.