The invention belongs to the field of ground penetrating radars, and discloses a variable gain equivalent sampling ground penetrating radar control system based on a CPLD. The system comprises an upper computer, an MCU microprocessor, a CPLD, a delay trigger circuit, an analog-to-digital conversion module, a transmitting module and a receiving module, wherein the upper computer is used for sendingan instruction and receiving a signal; the MCU microprocessor is used for realizing information interaction between an upper computer and the CPLD, the analog-to-digital conversion module is used forconverting the received electromagnetic wave signal of the receiving module into a digital signal, the CPLD is used for setting the total number of times of transmitting and receiving the electromagnetic wave signals, the transmitting time interval, the receiving time interval and the gain multiplying power; the delay trigger circuit is used for controlling whether the transmitting module and thereceiving module transmit or receive signals; and the receiving module is used for realizing equivalent gain sampling. According to the invention, surface deep weak signals are acquired, and the parallel processing capability and the detection precision of the control system are improved.