CCAST, World Lab, Beijing 100080, Peoples R China
; Univ Sci & Technol China, Dept Modern Phys, Hefei 230027, Peoples R China
; Inst High Energy Phys, Beijing 100039, Peoples R China
A systematical method is presented for solving the relativistic wave equations for particles of arbitrary spin. Explicit helicity relativistic wave functions for particles with arbitrary spin are derived rigorously.