Key and assembling method thereof

The invention relates to a key and an assembling method thereof. The key includes a base plate, a key cap, a balance rod and a buffer piece. The base plate has a first engaging structure and a secondengaging structure. The key cap is arranged above the base plate. The balance rod has a balance rod upper end and a linkage end, and the balance rod upper end is movably connected to the key cap. Thebuffer piece includes a pivot engaging part and a buckle engaging part. The material of the buffer piece is soft than that of the base plate. The pivot engaging part is rotatably engaged with the first engaging structure. The buckle engaging part is engaged with the second engaging structure. The base plate and the buffer piece are adjacent to each other for together form a limit structure. The linkage end movably passes through the limit structure. When the key cap moves upwardly and downwardly relative to the base plate, the linkage end moves in the limiting structure correspondingly. The key of the invention produce