Mold steel has excellent high temperature performance and is widely used in the field of high temperature die casting. However, conventional mechanical machining is unable to fabricate complicated conformal cooling structures. Furthermore, regular selective laser melting (SLM) is inefficient to build mold steel H13 and it usually gives rise to interval cracks and local distortion. Consequently, in terms of fabricating mold steel H13 by SLM, this paper introduces a self-developed high-temperature SLM system and the innovative hybrid spot technology, including semiconductor laser preheating spot and fiber laser melting spot. When the scanning speed is 1800-2500 mm·s^-1 and the substrate is preheated at 250 °C, both individual and hybrid laser spots are used to perform the experimental study. The result indicates that the maximum density obtained under the suitable configuration of composite spot is better than that obtained by single spot with the same forming efficiency. In addition, the qualitative analysis is also performed on the action mechanism of the hybrid laser spot in view of energy input.