The invention relates to composite tea saponin, a preparation method thereof and use thereof. The composite tea saponin is prepared by mixing a proper a mount of water with raw materials including 1 to 3 percent of nano titanium oxide, 12 to 18 percent of tea saponin, 1 to 5 percent of methylcellulose, 23 to 45 percent of natural soap powder, 3 to 5 percent of infusorial earth, 6 to 12 percent of sepiolite and 5 to 10 percent of sodium carbonate. The preparation method mainly comprises: nano titanium oxide dispersion, dust-free compounding, granulation and synthesis, wherein the finished product is homogenized by a sieve and discharged in form of grains. The tea saponin can replace one or both of caustic soda and hydrogen peroxide as a finishing agent for use in the fields of textile, leather, paper making, sewage treatment and daily chemical industry. The preparation method can meet the original technical requirements of production and processing industries on the use of the caustic soda and the hydrogen peroxide, simplify technical process, avoid equipment corrosion and material damage, improve product quality, discharge waste water in an environmentally-friendly manner, ensure safety of human bodies, reduce production cost, save energy, labor and time and realize ecological, environmentally-friendly and safe production.