In this work, a method of building the single crystal microstructure with SLM technology is introduced, which is the selective remelting method (SRM). Two parameters RRx and RRz were created to indicate the remelting behavior of the melting tools. To apply the SRM, high remelting ratios need to be applied. The results show that with the SRM, the single crystal microstructure can be achieved in the core area of the component. Furthermore, the study looks deeper into the single crystal microstructure built by SLM. Different experimental conditions including the preheating temperature and cooling time were used. The result of the experiment shows the correlations of the microstructure and the temperature of the component as well as other build conditions. It also shows the possibility to control the microstructure by controlling the temperature of the built component. The current study also investigates the geometrical effects of the component on the single crystal growth behavior. Different geometrical characters were studied separately. The results show that different geometrical characters have different effects on the single crystal growth behavior. For the geometries with varied scanning vectors, a method was created to homogenize the melting and cooling conditions. The results in this experiment show the positive effects of this method on the stability of single crystal growth.