Thanks to its tunable direct-bandgap, high charge-carrier mobility and unique in-plane anisotropic structure, black phosphorus (BP) has become a rising star of post-graphene two-dimensional (2D) nanomaterials. However, BP is unstable in the ambient conditions which largely limits its application. In this paper, an organosilicon agent-TMSCl was used for surface coordination of BP nanosheets to generate TMSCl@BP, which would maintain surface morphology and properties for 24h in the ambient conditions and has no cytotoxicity at the concentration of 200 ppm as previous reports. Our study is the first evidence that bare BP can coordinate with organosilicon to generate more stable TMSCl@BP. Notably, the photothermal effect of TMSCl@BP was miantained after exposure under ambient conditions for over 24 hours.