Abstract: The blasting valve performs its valve opening function by detonating explosives through electrical signals. The lower shear cover of the blasting valve is a stainless steel forging. Under the condition of long-term high temperature, high pressure and irradiation in service, cracks and other dangerous defects may appear on the inner and outer surfaces of shear cover forging. Based on the structural characteristics of the shear cover, the ultrasonic testing technology combining ultrasonic phased array and ultrasonic surface wave detection was studied. Through the field application, the feasibility of the ultrasonic testing technology is verified, which may provide reference to other people working in the same field.