When using ultrasonic array probes for nondestructive testing, in order to ensure the accuracy and accuracy of the detection, the detection system needs simultaneous acquisition of ultrasonic signals from each channel of the array probe. The multichannel ultrasonic signal synchronous acquisition system is based on FPGA and STM32 microprocessor, FPGA chip is responsible for simultaneous data acquisition and cache ，as the master chip of the system, STM32 is responsible for transmitting control signals and data transmission. the system could collect 32 channels of ultrasonic signals synchronously at most.The system combines the advantages of FPGA and STM32 microprocessors, it has good working performance, parallel control of each A/D channel, synchronous acquisition of ultrasonic signals, through the Ethernet interface, the data is transmitted to the host computer for storage, display and subsequent data processing. The system is used for data acquisition of each channel of the array probe, the data has good synchronization, and can meet the requirements of synchronous acquisition of ultrasonic testing data.