A molecular dynamics simulation of confined n-alkanes has been conducted to investigate the effects of the chain length of lubricant molecule and normal load on friction and asperity contact. The density distribution and surface coverage of lubricant atoms were calculated. The simulation results indicate that longer chain n-alkanes can provide more atoms for the mono-layer in the asperity contact interface than shorter ones, which, as a result, significantly reduce the friction force when the asperity contact occurs. C64-alkanes molecules can form a mono-layer of lubricant to avoid direct asperity contact at pressures up to 1000. MPa.