The invention relates to a preparation method of a graphene coating conductive fiber. The preparation method comprises the steps that graphene oxide is assembled on a fiber by electrostatic interaction, and then subjected to reduction treatment to obtain the graphene coating conductive fiber, wherein the assembly is achieved by immersing the fiber with charges on the surface in a graphene oxide dispersion at a temperature of 10 to 30 DEG C for one or more times, the graphene oxide in the adjacent two immersed graphene oxide dispersions is oppositely charged each time, the soaking time is 5 to10 min each time, and post-treatment is conducted after each soaking; multiple soaking is 2 to 8 times; the conductivity of the obtained graphene coating conductive fiber is 10 to 1.5 multiply 10<3>S/m, and the conductivity remains above 95% or more after washing for 100 times. The preparation method is simple, the fiber coating efficiency is effectively improved by an electrostatic assembly method, the used coating layer is all graphene, the electrical conductivity and water washing performance of the fiber are significantly improved, and the preparation method of the graphene coating conductive fiber has a great application prospect.