The present invention discloses a long-acting flame retarding coating fabric with safety protection performance, and a preparation process thereof. According to the fabric, a first prime coat and a second prime coat are provided; a surface coating comprises a polyurethane resin, bromoethane, antimony oxide, and zinc borate; and a lining woven from a flame retarding polyacrylonitrile fiber silk is adhered to the other side of a coating layer, wherein the flame retarding polyacrylonitrile fiber silk comprises polyacrylonitrile fiber, cotton and aramid fiber, and a ratio of the polyacrylonitrile fiber to the cotton to the aramid fiber is 4:3.5-4.5:0.9-1.1. The preparation method comprises: respectively soaking and dissolving bromoethane, antimony oxide and zinc borate powder in toluene for at least 24 hours; uniformly mixing the bromoethane, the antimony oxide, the zinc borate powder and a hydrophilic polyurethane moisture permeation primer according to a mass ratio of 40:22-18:4-6:95-105 to form a prime coat slurry; mixing polyacrylonitrile fiber, cotton and aramid fiber according to a mass ratio of 4:3.5-4.5:0.9-1.1, silking to form the flame retarding polyacrylonitrile fiber silk, and adopting a flame retarding lining woven from the flame retarding polyacrylonitrile fiber silk, and adhering on the other side of the surface coating; and uniformly mixing a white slurry and a surface coating slurry to form a blended surface coating slurry. With the fabric of the present invention, the flame retarding time is long, the amount of the smoke generation is small, the droplet is not easily generated, the flame retarding effect is resistant to washing, and the hydrolysis of the flame retarding substances is avoided.