Abstract: Provided are a method of preparing a polyurethane prepolymer with high functionality and the polyurethane prepolymer with high functionality prepared therefrom and a curing agent comprising the same. The method includes the steps of: Step (A): providing an alcohol composition comprising a first polyol having 2 or 3 OH groups and a second polyol having 4 or more OH groups; Step (B): reacting the alcohol composition with a polyisocyanate to undergo a first polymerization, so as to obtain an intermediate; wherein a molar ratio of a total number of the OH groups of the alcohol composition to a total number of NCO groups of the polyisocyanate is from 1:2 to 1:6; and Step (C): adding a catalyst to carry out a second polymerization of the intermediate to obtain the polyurethane prepolymer with high functionality, which has four or more NCO groups.