The invention relates to water-based 
polyurethane adhesive with high 
adhesive property and a preparation method thereof, and belongs to the field of 
polyurethane adhesive. The preparation method comprises the following steps: (1) 
drying a polylol 
polymer for 1 to 3 hours in vacuum at a temperature of between 100 and 120 DEG C, reducing the temperature to between 80 and 90 DEG C, dripping diisocyanate into the polylol 
polymer, polymerizing the mixture for 1 to 1.5 hours, adding small molecular polylol and hydrophilic polylol into the mixture to carry out chain extension and 
polymerization reaction for 1 to 1.5 hours, then adding the diisocyanate into the mixture, and making the mixture subjected to end capping reaction for 0.5 to 1 hour; (2) dripping neutralizing agent into cross linking 
polyurethane pre-
polymer, and adding 
acetone into the pre-polymer at the same time to reduce 
viscosity, wherein the 
neutralization degree is 95 to 100 percent after the mixture is reacted for 0.5 to 1 hour at a temperature of between 35 and 45 DEG C; (3) dripping the obtained hydrophilic cross linking polyurethane pre-polymer into a mixture of a 
polyamine compound and water, and dispersing the mixture evenly under high-speed shearing function of an emulsifying 
machine to obtain water-based polyurethane dispersant; and (4) removing 
organic solvent in the water-based polyurethane dispersant obtained in step (3) by a vacuum decompressing method. The preparation method effectively solves the problem of difficult emulsifying dispersion caused by cross linking, has simple emulsifying process, and reduces 
equipment requirement remarkably, has high 
solid content, reduces cost for production, storage and transportation, improves 
drying time, and is convenient for gluing operating process.