The invention is related to protector of start up procedure for not controllable rectification circuit with capacitance of large capacity as filter. The suppressor includes a start up protector for rectification circuit, comparator of voltage detection at input and output ends of connection point at main loop, integral comparator, protection locking circuit, reset circuit, and circuit for outputting signal of control junction of DC relay in small power, which are all integrated and encapsulated except the current limiting resistance. When protecting circuit is in normal operation, the invention protects the start up of the rectification circuit, and restrains initial charging current for filtering electrolytic capacitor. When protecting circuit is in fault, the invention cuts off relevantpower source to protect self. The rated current at junction of main loop can reach to 200A, but its control power is small and quantity of heat generated is also small.