With a background of industrial roller chains,the effect of surface grooves on the thermal elastohydrodynamic lubrication(EHL)problem between sleeve-pin pair in roller chain under a condition of sufficient oil supply was studied.Based on an assumption of long elliptical contact,a steady-state thermal EHL model was established by using two kinds of surface grooves,the longitudinal groove and transverse groove.It is found that when two symmetrical longitudinal grooves are arranged at both ends of the long elliptical contact area,oil is stored there and local thicker film thickness is realized.When three symmetrical transverse grooves are arranged at both ends of the elliptical contact area along the long axis,oil film thickness,pressure and temperature at the edges of the groove are fluctuated sharply,generating an enhancement in the dynamic effect.The effect of transverse groove is better than the longitudinal groove.