The invention discloses a realization method of synchronous collection. The method can reach the goal of reducing the device cost, and comprises the following steps that: a computer and a low-sampling-speed instrument are connected, an interface design is carried out on the computer to obtain a synchronous collection software setting interface, the parameter setting is carried out on the interface, the time format of the set character strings is converted into time data using seconds as units, each channel is subjected to data collection, the collected data is stored into a two-dimension array, the digital quantity in the two-dimension array is converted according to the analog-to-digital conversion principle of an adopted analog-to-digital converter (ADC), in addition, a Y-axis sampling amplitude value of each channel before the synchronization is obtained, the actual sampling time of each Y-axis sampling amplitude value is calculated and is recorded as X-axis data, a polynomial curve fitting function is adopted for carrying out polynomial fitting on X-axis and Y-axis data by aiming at the synchronized channel, a fitting curve of the synchronized channel is obtained, each X-axis data of a reference channel is introduced into the fitting curve, and the alignment of the waveform of each channel is realized.