The invention discloses a well and canal combined saline land improvement system and an improvement method thereof. The improvement system comprises a chequered field, ridges, a traffic way, irrigation canals, an underground water control system and a control room. The chequered field is separated by the ridges, the irrigation canals are located on the two sides of the chequered field, and the traffic way is arranged on the side of the irrigation canals. The underground water control system comprises a drainage closed conduit, a shallow water radiation well and a water suction pump. The shallow water radiation well is arranged in the chequered field in the region needing to be improved according to the control range of the well, the drainage closed conduit is buried in the chequered field, a water outlet is formed in the shallow water radiation well, the water suction pump is mounted in the shallow water radiation well, and a water outlet of the water suction pump stretches into the irrigation canals. The control room comprises a control box and a displayer, and the control room is arranged on the traffic way of the chequered field and connected with a water suction pump control switch. Soil flushing can be carried out through the wells and the canals in combination with irrigation and drainage measures, underground water can be collected, and secondary salt accumulation caused by the high-salt-content underground water level can be effectively avoided. Littoral beach salinity soil can be effectively improved.