Safety protector for open mill

The invention relates to a safety protector for an open mill. A protective screening is arranged at the rear of the open mill; a mounting door is arranged on the protective screening; a safety bolt is mounted on the mounting door; an emergency-stop pedal switch is arranged below the open mill; a trigger point is arranged on the emergency-stop pedal switch; the emergency-stop pedal switch is connected with a limit switch A; a safety push rod is arranged in the middle of a front roller; a limit switch B is arranged behind the safety push rod and fixed to the safety push rod; a vision sensor A and a vision sensor B are arranged at the two sides above the open mill; the two sensors face to the joint position between the front roller and a rear roller; in the using process, a safety relay monitors an accessed normally closed contact, so that in the emergency circumstances, the personal safety of an operator can be ensured; when the vision sensors detect the situation that in the sizing material extrusion area, an object different from the sizing material in color enters into the detection area, the safety protector can immediately stop the machine and give an alarm, so that the safety of staff can be guaranteed to the largest extent.