The present invention provides a polyacrylic acid copolymer emulsion, an organic-inorganic composite waterproof coating, preparation method thereof, and a waterproof coiled material. It can solve the problem that the granules dropping out from the prior waterproof membrane easily. The organic-inorganic composite waterproof coating according to the invention is prepared by compositing organic granules and inorganic granules, wherein the organic coating locks the inorganic granules, and prevents the inorganic granules from dropping out. Some exposed inorganic granules take part in the cement hydration reaction, and increase the bonding strength with the post-poured concrete. Furthermore, the organic-inorganic composite waterproof coating according to the invention does not need a buttering. It can reduce waste without an adhesive-resist insulation film/paper. Experiments prove that the peeling strength between the organic-inorganic composite waterproof coating and the concrete according to the invention is above 2.0 N/mm after being exposed to the sunshine for 8 weeks.