The invention discloses a method for evaluating segregation of a continuous casting blank through hardness. A flat section is cut on a hot-rolled continuous casting blank, the cut appearance is subjected to hardening and tempering, points are taken from the cross section and the longitudinal section of the casting blank after hardening and tempering, and the (Brinell) hardness is measured by dotting the taken points. The segregation of the continuous casting blank is ultimately evaluated by comparison of hardness values. According to the method, a specific steel grade can be evaluated, the method is convenient and simple, does not need to carry out cutting sampling on the casting blank and is low in cost compared with a traditional direct reading spectrum. According to the method, the objectivity and accuracy of inspection are ensured, and the inspection efficiency and cost are improved. The method is novel and can be used in a large scale, and the practice shows that the method has good practical effect.