The structural, magnetic and electrical properties of Co2MnSi thin films grown onto n-doped Si(110) and n-Si(100) substrates were studied. The structure and magnetic properties of Co2MnSi thin films were found to depend strongly on the annealing temperature (TA). At TA = 275-350degC, the Co2MnSi films were of B2 phase with lang100rang texture and possessed magnetic moment on both substrates. The saturation magnetization (MS) of Co2MnSi thin films was found maximum at TA = 300degC. Chemical reaction might occur between Co2MnSi and Si above TA = 350degC which caused nearly zero MS value. The current-voltage (I-V) characteristic of the Co2MnSi thin films onto n-Si substrates was obtained linear suggesting the contacts were ohmic nature.