Battle damage assessment in TBM reentry interception is studied from the perspective of tracking radar. Firstly, the paper analyzes two kinds of circumstances when reentry TBM is intercepted. Based on this, the ballistic coefficient method is applied to TBM battle damage assessment, and a method of calculating ballistic coefficient is introduced. Then a method of TBM Battle damage assessment based on ballistic coefficient estimation is put forward. By simulating the ballistic coefficients of three ballistic targets complete warhead, wreckage and litter pieces, the assessing method proved to be available. The influence of radar measurement accuracy on the evaluating error of ballistic coeficient is analyzed by simulation, and it comes to the conclusion that the improvement of radar measurement accuracy benefits the assessing accuracy of TBM battle damage. Finally, the effect of target maneuver on assessment is studied by simulating the warheads' contrails in maneuver-shifting contrail model and in collision-shifting contrail model, and the solution is summarized to avoid this effect.