The invention discloses a control device for hail impact test and an operation method thereof. The control device comprises an upper computer and a lower computer; wherein the upper computer comprises an LED velocity indicator, a first microprocessor, a first controller, an optoelectronic isolator, a first communication module, a control valve, a switch and a boost controller; the lower computer comprises a first photoelectric sensor, a second photoelectric sensor, a second microprocessor, a second controller and a second communication module; the operation method comprises the following steps: by utilizing the boost signal and the sending signal of the first controller, respectively starting an air booster pump and sending hail balls through the first microprocessor and the optoelectronic isolator, the hail balls respectively passing through the first photoelectric sensor and the second photoelectric sensor to obtaining an interrupt signal, calculating the hail ball velocity signal through the second microprocessor, and sending the hail ball velocity signal to the LED velocity indicator via the communication module and the first microprocessor. The invention realizes the requirement on multiple sending in hail tests in a short period of time, and ensures the sending conformity and data accuracy.