A method for manufacturing a golf club head includes producing a main body wax pattern and an accessory wax pattern. An engaging portion of the main body wax pattern is engaged with an engaging portion of the accessory wax pattern, with a gap being defined between the first engaging portion and the second engaging portion. Then, a low-viscosity volatile solvent is filled into the gap for forming a club head wax pattern by means of bonding of dissolved wax materials of the main body wax pattern and the accessory wax pattern. The club head wax pattern is impregnated in slurry to form a ceramic shell, which is then heated the ceramic shell to release wax in the ceramic shell. Finally, a casting procedure is carried out to form a club head casting in the ceramic shell.