A new doping method of BP by integration of density-controlled monolayer MoS₂ nanoparticles (NPs) is demonstrated. MoS₂ NPs with different density were synthesized by chemical vapor deposition (CVD) and transferred onto a few-layer BP channel, which induced a p-doping effect. The hole concentration of BP was controlled with different densities of MoS₂ NPs in a range of 10¹² - 10¹³ cm^-2. The doping mechanism was explained by a charge transfer by work function differences between BP and MoS₂ NPs, which was confirmed by Kelvin probe force microscopy (KPFM) and electrical measurements. Raman and X-ray photoelectron spectroscopy (XPS) were measured to confirm the oxidation on the edge of MoS₂ NPs and a doping effect of MoS₂ NPs on a BP channel. This result shows promising possibility for BP device functionalization by decorating various NPs, which will enhance the device performance such as photoresponsivity, or chemical sensitivity.