The invention relates to a manufacturing domain of nanopowder composite, especially to a nano antibacterial powder coating and one-step manufacturing method of microsuspension. The nano antibacterial powder coating consists of water, mixture monomer, pigment, surface processing agent, nanometre-sized inorganic antiseptic particle and auxiliary agent. The method comprises dispersing components such as water and suspending disperser by ultra-audio wave, then performing dispersion by high-shear emulsifier to prepare the predispersion; afterwards, adding the other components into polymerization kettle according to priority, after agitation and heating, adding the said predispersion at one time, reacting at a constant temperature, then cooling, discharge, centrifugally dewatering and drying to obtain the product. The invention solves the problems that the nanoparticles are easy to aggregate inside the organic polymer existed in present technology and the manufacturing engineering of the traditional powder coating is difficult, and has advantages that the process flow is short, the equipment investment is low, and can save working hours and energy resource, is of no dust pollution, the prepared powder coating particles is of regular shape, and has better levelling property in application.