The invention belongs to the technical field of building materials, and particularly relates to a long-acting insect expelling and purifying functional coating and a preparation method and a construction method thereof. The coating consists of a coating A and a coating B, wherein the coating A is prepared from the following raw materials in percentage by mass: 15 to 25 percent of talcum powder, 18to 25 percent of ground calcium carbonate, 8 to 15 percent of shell powder, 12 to 20 percent of ash calcium powder, 5 to 8 percent of bentonite, 1 to 3 percent of rubber powder, 2 to 6 percent of lemon eucalyptus alcohol, 1 to 4 percent of a pyrethrin agent, 5 to 10 percent of folium artemisiae argyi powder, 2 to 5 percent of lemongrass powder, and 2 to 4 percent of natural perfume; and the coating B is prepared from the following raw materials in percentage by mass: 85 to 95 percent of a basic paint, 2 to 8 percent of hexacyclic stone, 2 to 5 percent of germanite and 1 to 5 percent of infrared ceramic powder. The coating integrates insect expelling and air purification functions, has the characteristics of environmental friendliness, health, long-acting effect, durability, nature, high efficiency, sanitation, disease prevention, energy conservation and emission reduction, and can improve the living environment for people; and the preparation method and the construction method are simple and feasible.