Considering insufficient accuracy and real-time performance of traditional threat assessment method of multi-target in air combat, a new method based on fuzzy theory and DS evidence theory was proposed.BPA of threat index, fused in index and time domain through an improved fusion rule instead of traditional Dempster fusion rule, was calculated through setting membership grade function reasonably.Valuation and sequencing of each target threat was made by weighted summation.Finally, an example indicated that the method was effective.