A four-channel high-capacity waveform storage system comprises an FPGA core chip, an FPGA core chip minimum peripheral circuit, ADC sampling chips, a Flash array, an internet port circuit and a power supply chip. 9A, 9B, 9C and 9D in the power supply chip convert a 5V power voltage into a 3.3V voltage, a 1.8V voltage, a 1.0V voltage and a 2.5V voltage respectively for other modules to use; after being normally powered on, the FPGA core chip controls the four paths of ADC sampling chips to collect waveform data from an external input interface and transmits the data to the Flash array; after storage, the FPGA core chip controls the internet port circuit to transmit the data in the Flash array to an upper computer through an internet port; all control instructions are transmitted to the FPGA core chip by the upper computer through a network interface. A construction method of the four-channel high-capacity waveform storage system includes seven steps. According to the four-channel high-capacity waveform storage system and the construction method, multiple paths of waveform data can be integrally and simultaneously collected, and implementation is simple; the logical functions are all written in a VHDL and easy to modify; the four-channel high-capacity waveform storage system is small in size and can be conveniently applied to multiple systems.