The invention discloses a positioning tool and a process for the assembly of a reverse shift fork component. The positioning tool comprises a base plate. A fixed block is arranged on the base plate. A positioning mechanism for the assembly of the reverse shift fork component is arranged on the fixed block. The bottom of the base plate is provided with a pin hole fitting a positioning pin on a housing joint face and a positioning post fitting a process hole in the housing joint face. The specific position of the reverse shift fork component on a transmission housing is determined through the positioning tool; accordingly, such defects as poor fitting and unsmooth shifting caused by manufacturing tolerances of parts are overcome, and assembly is more accurate and uniform. The positional precision of the reverse shift fork component and that of the transmission housing can be adjusted through the positioning mechanism; accordingly, precision of fitting between a shifting mechanism and the reverse shift fork component is guaranteed indirectly, and the service life of the reverse shift fork component is prolonged.