The utility model discloses an ultrasonic wave passes board that shakes belongs to the defrosting part on the evaporimeter among the refrigerating plant, installs on the finned tube type evaporator who has ultrasonic wave defrosting function, is connected with ultrasonic transducer and heat exchange tube (the liquid pipe of circulation medium). Including dull and stereotyped, there is first curb plate at one side of flat board edge joint, it has the first diaphragm orifice of inserting inlet line to arrange on first curb plate, has the second curb plate relative with first curb plate at the opposite side edge joint of flat board, and it has the second diaphragm orifice coaxial with first diaphragm orifice to arrange on the second curb plate. It is simple to have overall structure, and energy transfer efficiency is high, and the difficult decay of ultrasonic energy presses down the advantage white, that defrosting effect is good.