The invention discloses a TDOA (time difference of arrival) positioning method, device and system based on time difference calculation. The method includes the steps: measuring and receiving signals transmitted by the same radiation source by receiving nodes of a plurality of measuring stations; processing the signals to remove high-frequency section spectrum line data of the signals, and transmitting the processed signals to a control center; receiving signals processed by different measuring stations by the control center; screening low-frequency section effective spectrum line data of the signals to remove spectrum line data with low contribution degree for time difference calculation; cutting down spectrum line amplitudes with low contribution degree for time difference calculation inthe signals processed by a discretized weighting function to obtain a cross-power spectrum density function, and calculating time difference to perform TDOA positioning. According to the method, noisesensitivity is reduced, the resolution ratio of time delay meets engineering requirements, transmitted data are suitably compressed, and real-time processing of the control center is accelerated.