The invention discloses a method for preparing an all-bio-based photocuring activated monomer and an application of the all-bio-based photocuring activated monomer. The preparation method includes the steps that a bio-based hydroxyl compound containing stiffness rings or a modified bio-based hydroxyl compound containing stiffness rings, triethylamine and solvent are mixed, undecylenylacyl chloride is dripped slowly under the ice-bath condition, the temperature is rise to an indoor temperature to further react for 12-36 hours after reacting is conducted for 2-4 hours, suction filtration, liquid phase washing, drying, suction filtration and rotary evaporateion are carried out, and accordingly the all-bio-based photocuring activated monomer is obtained. According to the application of the all-bio-based photocuring activated monomer, 5-40 parts of all-bio-based photocuring activated monomer, 100 parts of all-vegetable-oil-based polyenoid photocuring prepolymer, 10-60 parts of multi-mercapto compound and 2-8 parts of UV-light 1173 photoinitiator, by weight, are evenly mixed, and then an all-bio-based ultraviolet curing coating is obtained. Double bonds contained in the all-bio-based photocuring activated monomer prepared through the method are located at the end positions, so that the reactivity is high. The content of renewable carbon atoms is 100%, and thus dependence on oil resources is relieved.