The invention provides a drying agent for polyurethane synthetic leather and a preparation method thereof. The drying agent has excellent drying performance, and the hydrolysis resistance of the products is effectively improved by adding the drying agent into the polyurethane synthetic leather. The drying agent is solution of fluorine-containing polyurethane resin, and the weight percentage concentration of the solution is 19.94 to 80 percent. The drying agent comprises the components of an effective solid matter A, a solvent B and an aid C, wherein A is fluorine-modified polyurethane resin and can be expressed by a general formula, namely PFm(PULink)nXk, wherein PF is a chain segment generated by reacting fluorine-containing alcohol with 2 to 18 carbon atoms with an isocyanate group; the PULink is a polyurethane molecule chain segment generated by reacting a polyol compound with diisocyanate and comprises 8 to 16 repetitive units of carbamate; X is a chain or cyclic group and has 2 to 20 carbon atoms; m is an integer from 2 to 8; n is an integer from 1 to 8; k is a number from 1 to 3; m and n can be equal or unequal; and the aid C is modified organosilicon and an addition amount of the aid C is 0.06 to 1.2 percent.