As a promising powder-based additive manufacturing (AM) technology, selective laser melting (SLM) has exhibited excellent potential in many frontier fields in recent years [1]. However, it is expensive, time-consuming, and challenging to conduct in-situ observation of melting pool and obtain phase change phenomena by experimental studies. Hence, numerical simulation of SLM has attracted more and more researchers [2,3]. Smoothed particle hydrodynamics (SPH) is a meshfree method, which is widely used in modeling problems associated with complex interfaces [4] and therefore it is an ideal method to simulate melt pool behaviors. In this work, we establish a GPU-accelerated SPH model to simulate the melting and solidification process of SLM, with speed-up of over hundred times compared with the Single-CPU-based strategy. A modified Gaussian distribution is proposed to model laser heat source, which can accurately identify the laser thermal loading surface with complex geometric shapes. An improved single-phase continuous surface force (CSF) model is developed to ensure the accuracy of surface tension. The entire process of SLM including single-layer and multi-layer formations are simulated, and melt pool width and depth are consistent with experimental observations available in literature.