The realization of wurtzite structure II-VI material would overcome the problem associated with the lifetime of the devices. ZnCdS epilayers were grown on GaAs(0 0 1) and(1 1 1)B substrates, and crystal structure was controlled, ZnCdS eyilayers grown on GaAs(0 0 1) substrates showed slight signs of the wurtzite phase. Phi (phi) scan of the X-ray diffraction was performed, and ZnCdS epilayers grown on GaAs(1 1 1)B substrates showed mixed crystal structures. The substrate temperature and the Cl doping would affect the volume ratio of the wurtzite structure.