The invention discloses a preparation method of a bonding agent for a paper tube. The preparation method comprises the following steps of 1, placing deionized water, 
polyvinyl alcohol and the like in a reaction kettle, performing stirring and temperature rise, adding 
sodium dodecyl 
benzene sulfonate and the like, and performing stirring, 2, adding 
alkylphenol polyvinylether carboxymethyl 
sodium and the like, and continuing to perform stirring, 3, adding a konjak 
powder solution and the like, and continuing to perform stirring, 4, adding compound 
starch and the like, and performing stirring and temperature rise, and 5, adding an enzymatic 
hydrolysate and the like, and performing stirring and filtering, wherein a preparation method of the konjak 
powder solution comprises the concrete steps of uniformly mixing konjak 
powder, cetyl trimethyl 
ammonium bromide and the like, adding a 
chloroauric acid solution, performing stirring until a brilliant yellow color becomes clarified, adding a concentrated HCl solution, performing stirring and standing, adding a 
chitosan solution, performing mixing, and performing ultrasonic treatment and 
centrifugation to take a supernate. The prepared bonding agent has the benefits that the bonding agent is short in paper 
fiber breaking time, high in 
bonding strength, good in flowability and good in storage stability.