The invention relates to a multi-stage evaporation and air-vapour hybrid system and method thereof, comprising a multi-stage evaporation tower, a cascade control system for feeding a liquid charging stock, a heater and three nozzles. The multi-stage evaporation tower comprises a tower body and a tower base divided into three segments with two dividing tower plates. The tower body is provided withan air-vapour outlet, a feeding inlet, an air-vapour inlet, a liquid outlet and a leakage fluid drain. The method provided by the invention comprises the following steps: the liquid charging stock isshunted and regulated through the cascade control system, and then fed into an upper tower body of the multi-stage evaporation tower and the heater, and a liquid mixture is heated in the heater. The air is loaded into the nozzle, the liquid mixture is mixed and evaporated in the heater, then air-vapour mixture is fed into the multi-stage evaporation tower. The air-vapour mixture product is discharged from the top and a residual liquid is further discharged. The invention realizes multi-stage evaporation and condensation of the mixture liquid through a plurality of nozzles and multi-stage evaporation tower system, and control is simple.