GaN films were grown on 3C-SiC/Si(III) substrate using GaN, AIN, and GaN/AlN superlattices as the buffer layer in a metal-organic chemical vapor deposition (MOCVD) system. The surface morphology and structural and optical qualities of the GaN films were greatly improved by employing the buffer layers in the growth of GaN film on the 3C-SiC/Si substrate. The use of the superlattice buffer laver produced well-oriented GaN growth along the c-axis with good surface morphology. Low temperature photoluminescence (PL) measurements showed that peaks associated with band-edge emission and donor-accepter pair recombination (D(0)A(0)) were observed from GaN films grown with and without GaN or AIN buffer layers, whereas GaN films grown with the superlattice buffer layer exhibited a strong band-edge peak with very weak D(0)A(0) emission. The surface morphology and structural and optical properties of the GaN films were well correlated for the evaluation of GaN crystal quality.