The invention provides a faucet handle assembly which can be installed to penetrate through a body set on the platform surface. The faucet handle assembly comprises handle parts (4), handle bases (3), bushing structures (2) and a pushing mechanism, wherein each handle part (4) is provided with a rod portion (41), a valve rod (51) and a connecting portion (42), the valve rods (51) can be connected to the body set, each connecting portion (42) rotates together with the corresponding valve rod (51), the handle bases (3) are placed on the platform surface or a face plate (8) arranged on the platform surface in a gapless mode, and are connected with the body set, each handle base (3) is provided with a through hole and a blocking portion, each connecting portion (42) is contained in the corresponding through hole, the blocking portions are arranged on the walls of the through holes, each bushing structure (2) is installed in the corresponding through hole, and is provided with a radial deformation portion and a locating portion, at least one part of the portion, surrounding each connecting portion (42), of the corresponding bushing structure is located through the corresponding locating portion, each radial deformation portion is set to be switched between the natural position and the offset position, each radial deformation portion abuts against the corresponding blocking portion when being at the offset position and is separated from the blocking portion when being at the natural position, and the pushing mechanism is used for pushing the radial deformation portions to be located at the offset positions in the state of assembling the handle assembly. The invention further provides a method for assembly of the handle assembly and a method for installation of the handle assembly.