Aimed at the problems that in the air combat, the traditional CRITIC (Criteria Importance Though Intercriteria Correlation) method is hard put to assess situation to achieve variable weights, assigning weights are only begging from the attributes of the data itself, expert opinions are neglected, and the CRITIC method itself makes image jitter, a sliding window CRITIC-G1 based close air combat situational assessment method is proposed. The method is to pre-processes the air combat data to obtain a dominance function matrix with change according to time, decompose the dominance function matrix by adopting the sliding window method, and assign CRITIC-G1 weights to the dominance function matrix in the sliding window, achieving both variable weights and the importance ranking-based weighting optimization. Simultaneously, the coefficient of variation is introduced to reduce the combined dominance function image jitter. The final output is the combined dominance function values of the aircraft, and the results of the situational assessment are obtained by analyzing the combined dominance function values of the two aircraft. The experimental results show that the sliding-window CRITIC-G1 method is an accuracy increase of 22.75%.