Boron Phosphide (BP) has gained significant research attention due to its unique photoelectric and mechanical properties. In this study, we investigated the stability of BP under high pressure using X-ray diffraction (XRD) and scanning electron microscope (SEM). The phase diagram of BP was explored in both B-rich and P-rich environments, revealing crucial insight into its behavior at 5.0 GPa. Additionally, we measured the melting curve of BP from 8.0 GPa to 15.0 GPa. Our findings indicate the stability of BP under high pressure will be improved within B-rich and P-rich environments. Furthermore, we reported a remarkable observation of melting curve frustration at 10.0 GPa. This study will enhance our understanding of stability of BP under high pressure, shedding light on its potential application in semiconductor, thermal, and light-transmitting devices.