An assembling mechanism of a discharge pipe and a method thereof, capable of preventing deformation of an upper cover and a compression unit generated in assembling the discharge pipe by improving assembling mechanism of the discharge pipe, thus to improve performance of the compressor. The assembling mechanism includes an upper cover on which a guide member having a discharge pipe inserted therein is mounted, a muffler in which an insertion hole having the discharge pipe inserted therein is formed, a first connection portion for welding/combining the discharge pipe and the muffler after inserting the discharge pipe in the insertion hole and a second connection portion for welding/combining the upper cover and discharge pipe.