Method of improving steel object surface hardness using carbon distribution

The present invention relates to a method for raising steel component surface hardness by adopting carbon distribution, belonging to the field of heat treatment technology. Said method includes the following steps: firstly, coating side surface of workpiece with a layer of coating layer which is resistant to high temperature and does not transfer heat, then austenizing said workpiece and promptly placing the austenized workpiece into quenching medium, the interior of workpiece side surface which is not coated with heat-resisting coating layer can be instantaneously converted into martensite and most of side surface coated with heat-resisting coating layer still is austenite, then promptly quenching workpiece up to 200-400 deg.C, and heat-insulating for 10-2000s, in this course the carbon can be quickly diffused into side surface austenite from martensite so as to make its surface richly contain carbon, finally making the workpiece be quenched in water, so that the workpiece side surface can be hardened.