The present study reports the synthesis of polycrystalline Zn_xCd_(1-x)Te (x = 0,0.025, 0.050,0.075 and 0.100) using the chemical reaction in terms of ball milling. Ternary Zn_xCd_(1-x)Te thin films were grown onto glass substrates at the temperature of 373 K using thermal evaporation technique. X-ray diffraction study showed that films are polycrystalline with cubic phase, which are preferentially oriented along the (111) direction. The refractive indices have been evaluated in transparent region using the envelope method, which has been suggested by Swanepoel. The optical energy gap were calculated in the strong absorption region of transmittance and reflectance spectrum. It was observed that the refractive index, n, decreases but the energy gap increases with increasing the dilute Zn, at expense of Cd, in Zn_xCd_(1-x)Te thin films.