The invention discloses a multifunctional high-strength composite fabric coating agent, a coating, and a preparation method and application of the multifunctional high-strength composite fabric coating agent. The multifunctional high-strength composite fabric coating agent comprises resin, a reinforcing agent of which the surface is provided with active groups, a difunctional dispersing agent, a levelling agent, a film forming agent, a softening agent, an antibacterial agent, a solvent and the like, wherein the reinforcing agent is subjected to surface modifying treatment and is provided with the active functional groups, such as -OH and -NH3. The fabric coating agent provided by the invention is convenient to apply, high in acting speed and stable in characteristics, and is basically suitable for the surfaces of fabrics made of any materials; moreover, the fabric which is treated by the fabric coating agent has very great tensile breaking force, excellent bursting performance and tearing performance, high waterproofing and moisture-penetration performance and antibacterial performance, and high adhesion force, can also be scraped and coated, rolled and coated, calendered or soaked repeatedly; and moreover, the preparation method of the coating agent is mature in process and low in production cost, and is suitable for large-scale popularization and application.