Abstract: Chemical compositions of “Jin Mo” auto-restoration coating was analyzed by using XRD.With 50CC engine oil as lubricant,effect of auto-restoration coating on the friction-coefficient of 45 steel-steel tribo-pair were investigated.The variety of weight of the tribo-pair with time and micro-hardness of the worn surface were also studied.The results indicate that Mg₃Si₂O₅(OH)₄ in auto-restoration coating is the main substance to form the modified surface.Friction-coefficient decreases with addition of “Jin Mo” auto-restoration coating in engine oil and the friction-coefficient is down to minimum 0.0487 with 10% auto-restoration coating in 50CC engine oil,decreased by 61.04% compared with mere engine oil lubrication.At same time,the weight of tribo-pair increases with prolongation of wearing test time,and the HV of the grey blocks is about 404.96,2 times higher than that of 45 steel.