The ion composition of the tail current sheet is essential to understanding the Martian ion escape, however, our current knowledge is poor. Using measurements by Mars Atmosphere and Volatile EvolutioN (MAVEN), we investigate the density of different ion species in the Martian magnetotail current sheet. We find that events we survey of the current sheet, the average occurrence rate of current sheets with dominant heavy ions (O+ and O2+) is about 50%, while the rate of those with dominant H+ is about 20%. A current sheet closer to the terminator is mostly dominated by heavy ions, regardless of upstream solar wind, but it could be dominated sometimes by H+ when it is beyond the downstream distance of 0.75 RM (RM is Mars’ radius), where the occurrence rate of current sheets with dominant H+ (heavy ions) weakly increases (decreases) with solar wind density and dynamic pressure.