Aim at the problem of order-blur caused by low order fitting and difficult solve of fitting frequency integral equation created by high order fitting, a no tachometer order based on sparse signal decomposition combined with segmental fitting and integral approximation (NTO-SSDFIA) is presented. The instantaneous frequency is segmented according to the dynamic time support area (DTSA) and fitted by low order polynomial. The angle resample time ticks is ascertained by integral approximation instead of solving the equation, so the no tachometer order is carried out precisely. The experimental results of simulating signal and practical signal show that the rotating frequency changing simply in the segments whose number is least segmented by DTSA; the problem of low precision and bad adaptability of whole fitting by single polynomial is solved by the exact fitting in segments by low order polynomial; the influence of solution of equation on the result of order analysis is resolved effectively by integral approximation, which is able to ascertain the angle resample time ticks without solving the equation; The NTO-SSDFIA is an new effective method of the order analysis of rotating machinery under the condition of no tachometer.