The invention belongs to the technical field of coating preparation, and discloses a long-chain siloxy fluorosiloxane emulsion and an inorganic silicate coating modified by the long-chain siloxy fluorosiloxane emulsion and a preparation method of the inorganic silicate coating. The inorganic silicate coating modified by the long-chain siloxy fluorosiloxane emulsion comprises the following parts byweight: 100 parts of an inorganic silicate solution; 2 to 30 parts of the long-chain siloxy fluorosilicone emulsion; 10 to 50 parts of water; 0.5 to 4 parts of an antifoaming agent; 0.5 to 4 parts ofa dispersing agent; 0.1 to 4 parts of a leveling agent; and 100 to 200 parts of a filler. The invention also discloses the preparation method of the inorganic silicate coating. The inorganic silicatecoating can adopt the processes such as roll coating, spraying coating and brushing coating, the surface contact angle can reach 100 to 145-degrees, the inorganic silicate coating has water resistance and acid and alkali resistance, wherein the alkali resistance is 48 h without abnormality and resistance, the inorganic silicate coating has washability (1200 times without exposure), cracking, shedding, powder loss and other problems during the use of the inorganic silicate coating can be effectively prevented, and the inorganic silicate coating has a wide range of application in the field of high hydrophobic and high antifouling building interior and exterior walls.