In this research, effect of electroplating parameters such as etching time of base metal, bath temperature, and current density on some properties of hard chromium coating; such as hardness, thickness, and surface morphology, has been investigated. ST37 carbon steel with 0.17% carbon content, from low carbon steel grade, has been selected as the base metal of coats. Surface of the specimens were etched at different times; 20, 30, 40 seconds, prior electroplating. The specimens electroplated by hard chromium under different conditions of bath temperature (30, 40, 50, and 60 °C) and current density (15, 25, 35, and 45A/dm2). The results showed that increasing of current density increases the hardness, deposition rate (thickness) of coating, but increasing of bath temperature decreases coating hardness and deposition rate. Hardness of deposit decreases as etching time of the base metal increases. It seems that variation of etching time doesn't have significant influence on deposition rate. Crack free hard chromium deposit is obtained at 50 °C and 25A/dm2 deposition bath and variation of etching time doesn't any influence on producing of crack free hard chromium deposit.