Aiming at improve the accuracy of order holospectrum in the case of rotating speed fluctuation, the method of order holospectrum analysis based on FT zoom correction is proposed. Firstly, use order tracking based on the cubic spline interpolation to obtained stationary signals in angle domain from equiangular resampling of rotor unstable signal in time-domain, then, we can calculate more precision phase and amplitude of every order by FT zoom correction method, calculate the parameters of order holospectrum according to phase and amplitude, at last we will draw the picture of order holospectrum according to the calculate result. The analysis of simulation and analysis of flexible rotor’s vibration signal are presented to demonstrate that the method can obtain accurate order holospectrum, and also accurately determine the types of rotating machinery fault by the result of order holospectrum based on FT.