The invention provides a multifunctional drilling fluid additive and a preparation method of the multifunctional drilling fluid additive. The preparation method comprises a first step of heating water up to 35-70 DEG C; cation fluorocarbon surfactant, alcamines chemical compound and nonionic surfactant are respectively added under the condition of stirring. When the cation fluorocarbon surfactant, the alcamines chemical compound and the nonionic surfactant are all added, the mixture of the water, the cation fluorocarbon surfactant, the alcamines chemical compound and the nonionic surfactant are stirred for 0.5-2h. A second step of cooling down the temperature to 30-34 DEG C; antifoaming agents are added, and the water, the cation fluorocarbon surfactant, the alcamines chemical compound, the nonionic surfactant and the antifoaming agents are stirred and emptied to obtain the multifunctional drilling fluid additive. The multifunctional drilling fluid additive and the preparation method of the multifunctional drilling fluid additive are simple in craft and low in cost. The product obtained has the advantages of being lubricated, anti-sloughed and de-filtrated, and reducing surface tension and the like. The ability of resistance to temperature reaches 180 DEG C, and the multifunctional drilling fluid additive and the preparation method of the multifunctional drilling fluid additive can be applied for a deep well and an extradeep well, have good compatibility performance of the drilling fluid, and have no blighting effects on the drilling fluid.