The high complexity of modern battlefield and the incompleteness of various situational information make it difficult for the traditional air target threat assessment methods to be applicable to the case of lack of data.To solve this problem,firstly,the Improved Quantitative Biclustering Algorithm (IQBA) that introduces Isometric Logratio Transformation (ILT) and spherical coordinate transformation is used to complete the missed data of target attributes.Then,the improved entropy weight method based on the gray target theory and index correlation is used to analyze the influence degree of each attribute,and the weight of the target attributes is objectively calculated.Finally,the improved gray correlation TOPSIS method is used to assess the threat of the target in a combat mission and classify threat levels.The simulation experiment results show that the proposed method can effectively realize air target threat assessment under the condition of information shortage,and the assessment results are more objective and reliable.