The invention discloses a micro-channel heat exchanger with a visual collecting pipe and a method thereof. The micro-channel heat exchanger comprises the collecting pipe, wherein a visual window made of transparent material is arranged on the collecting pipe; the transparent material is preferably selected from non-crystallization polymer PSU. Through the micro-channel heat exchanger, the flow pattern maps of the collecting pipes of the micro-channel heat exchangers in different models under various working conditions can be shot by a high-speed camera; the flow path and allocation path of the heat exchanger can be improved according to the observing result, so that the intuitive improvement on the allocation of the micro-channel heat exchanger can be realized, and the flow of the heat exchanger is uniformly distributed. The heat exchanger with the collecting pipe visual window can be used as a condenser or an evaporator; the collecting pipe can be vertically placed, or can be horizontally placed. The positions and sizes of a collecting pipe slot, a flat tube slot, an inner allocation plate slot, a spacer slot, a refrigerant inlet and outlet slot in the models can be changed according to actual needs.