Abstract: The present disclosure provides an automatic door opening and closing actuator, belonging to the technical field of automobile components. The actuator includes a mounting housing and a push rod, wherein one end of the push rod extends out of a channel arranged on the mounting housing, and the other end of the push rod is arranged in the mounting housing to slide reciprocally, and further includes a sealing tube, wherein the sealing tube is sleeved outside the push rod, one end of the sealing tube is provided with an elastic covering ring wrapping the push rod, and the other end of the sealing tube is sealed and fixed to an inner wall of the channel or an end portion of the channel.