Heat treatment process of roller casting

The invention relates to a heat treatment process of roller casting. The process comprises the following steps that a cast roller is directly put in a heat treatment kiln for heating, and heated sequentially to a first heat preservation level, a second heat preservation level, and a first top temperature level, wherein heat preservation is conducted correspondingly on the first heat preservation level, the second heat preservation level and the first top temperature level; then first air cooling is conducted, the roller is re-put into the kiln after the first air cooling, heating is conductedto the second top temperature level, heat preservation is conducted, and then secondary air cooling is conducted; the roller is re-put into the heat treatment kiln after the secondary air cooling, after heat preservation is conducted on the third heat preservation level, heating to a third top temperature level is conducted, and heat preservation is conducted; and finally slow cooling is conducted, and the roller is taken