In view of the characteristics of many electromagnetic interference measurement parameters, measurement points and measurement conditions in complex electromagnetic environment and large-scale systems, the traditional sweeping frequency-domain measurement method has practical problems such as high cost and being time-consuming. This paper proposes a multi-channel time-domain rapid measurement and signal calculation method for low-frequency electromagnetic interference, and a multi-channel time-domain rapid measurement system for low-frequency electromagnetic interference is developed. The experimental results show that the proposed measurement, calculation method and the developed measurement system can accurately obtain the low frequency electromagnetic interference characteristics of complex electromagnetic environment and large-scale system, and the measurement speed is fast and the cost is low.