A pulse-electrodeposited Ni-Co-P/HBN composite plating and a preparation method thereof. The preparation method adopts a metal material as a substrate, and comprises the following steps: firstly pretreating the substrate surface, preparing a composite plating solution with nickel sulfate, cobalt chloride, sodium hypophosphite, citric acid, trisodium citrate, boric acid, and polyvinyl alcohol as main components and hexagonal boron nitride HBN powder as a dispersed phase, performing surface modification and dispersion treatment of the HBN particles by using a surfactant through ultrasonic vibration, allowing the HBN particles to disperse uniformly in the plating solution through reasonable setting of pulse electrodeposition parameters and full stirring, performing codeposition and heat treatment of the HBN particles and the substrate metal nickel cobalt phosphor in a state of applying pulsed current so as to obtain a corrosion-resistant, wear-resistant and antifriction pulse-electrodeposited Ni-Co-P/HBN composite plating. The invention overcomes defects of single component of current composite plating, coarse plating crystal grain, low interface bonding strength with the substrate, non-ideal comprehensive properties of corrosion resistance, wear resistance, and antifriction, and the like; the pulse-electrodeposited Ni-Co-P/HBN composite plating of the invention is applicable to wear-resistant, antifriction and corrosion-resistant surface plating of friction kinematic pair parts in industries of machinery, metallurgy, chemical engineering, and the like.