A novel approach is proposed to evaluate the tracking performance of photoelectric theodolite by testing its amplitude frequency characteristic curve.A method of testing the amplitude frequency curve is also given.At first,this paper analyzes the equivalence relations of describing a system using frequency characteristic,transfer functions,and differential equations（difference equations）.And then,the significance and the advantage of evaluating the tracking performance using the amplitude frequency characteristic curve of photoelectric theodolite are expatiated.The character of Wigner Ville distribution of tracking error which is gotten by tracking the optic dynamic target is described,when the frequency optic dynamic target is modulated continuously.The tracking error signal can be represented by a finite number of weighted sums for the base frequency harmonic and high harmonics,based on the characters of tracking error′s WVD.However,because of the lack of the scientific means to separate the harmonic components accurately,it cannot test the frequency characteristic curves using the time-frequency distribution.In this case,an indirect approach that test the amplitude frequency characteristic curve of photoelectric theodolite by using the line frequency modulation（LFM） signal is introduced.At last,the tracking performance and characteristic of the photoelectric theodolite are analyzed based on the amplitude frequency characteristic curve.