The invention discloses a microchannel heat exchanger which comprises a snakelike microchannel flat tube and a fin. The fin comprises multiple fin body parts which are arranged in an array and parallel manner. Each fin body part includes a first end and a second end which are oppositely arranged. The first ends of each row of adjacent fin body parts are connected through first connecting parts, and the second ends of each row of adjacent fin body parts are connected through second connecting parts. The fin is formed by bending along the first connecting parts and the second connecting parts. Flat tube slots used for containing first flat tube parts are formed between the adjacent fin body parts, the first flat tube parts are embedded in the flat tube slots, and the multiple rows of fins are folded to form flat and straight fin columns which are arranged neatly. Tight combination of the microchannel flat tube and the fin after welding can be ensured, the dust accumulation phenomenon is effectively prevented, the heat exchange area of the air side is enlarged, the heat exchange performance of the heat exchanger is improved, meanwhile, the assembling and manufacturing technology is simplified, and the production efficiency is improved.