In order to accurately and reasonably evaluate the target threat of synthetic unit, a target threat assessment method of synthetic unit based on improved principal component analysis (PCA) is proposed. Combined with the actual combat situation of synthetic unit and the influence of dynamic change of battlefield situation, the evaluation index system is constructed. Using triangular fuzzy analytic hierarchy process to calculate the relative weight of each index, an improved PCA threat assessment model is established, and the principal component coefficients are improved by weighting. The effectiveness of the model is proved by the example, and the results show that the method is consistent with the actual situation and can provide reference for threat assessment of synthetic unit.