In this work, Ag/CZTS/n-Si/Ag and Ag/CZTS/n-Si/Au heterojunction solar cells have been produced using PLD technique. The crystal size, microstrain, dislocation density and lattice constants of CZTS thin film have been calculated. CZTS thin film in 221-nm-thickness consists of particles in different size distribution and has a band gap of 1.60 eV. J- V curves of CZTS/n-Si solar cells produced with two different rear contacts have been obtained for the darkness and the illuminated environments. Ag/CZTS/n-Si/Ag heterojunction showed some better diode properties than other heterojunction structures in the darkness. Furthermore, a solar cell produced with Ag rear contact has indicated higher Jsc and efficiency values compared to one with Au rear contact. Au contact resistance and the interfacial recombination of charge carriers could lead to efficiency of CZTS solar cell to decrease. Photovoltaic parameters of these two solar cells have also been calculated by SCAPS-1D program. Experimental and theoretical results of solar cells have been compared and found to be compatible with each other.