The invention provides an intelligent diagnosis system and method for online fault monitoring of an efflux pump unit. The diagnosis system comprises the efflux pump unit, an acquirer, a multi-port repeater, a local monitoring unit and a remote monitoring unit, wherein the efflux pump unit comprises a motor and an efflux pump which are connected with each other; a vibration detection composite sensor is arranged on the efflux pump and is electrically connected with the acquirer; and the acquirer, the local monitoring unit and the remote monitoring unit are electrically connected with the multi-port repeater. By the intelligent diagnosis system and method for online fault monitoring of the efflux pump unit, the problems that an efflux main pump unit of an oilfield does not have a special online fault monitoring intelligent diagnosis system, vibration exceeds the standard for a long time, the efflux main pump unit is unsafe, electric energy is wasted, and shutdown is easily caused to result in loss are solved.