The tribological performance of GCr15 bearing steel under different lubrication conditions was investigated. The results showed that from lean lubrication to dry friction the tribological properties of GCr15 bearing steel change sharply and the wear mechanism transforms from abrasive wear to the mixture of adhesive wear and oxidation wear. Meanwhile, the thickness of the severe plastic deformation layer increases from lean lubrication to dry friction. The retained austenite transforms into the martensite on the worn surface and the residual compressive stress increases. The variation rate of friction coefficient (f ') and the time of the transition zone (ot) are proposed as the indicators of bearing early failure under unsteady lubrication, which are closely related to service conditions.