The invention discloses a high esterification degree 
isopropyl alginate preparation method, which comprises: adding 
alginic acid to 
anhydrous isopropanol, stirring, adding a dehydrating agent having the same 
molar water content as the 
alginic acid, adding a catalyst, carrying out stirring heating to achieve a 
reflux state, adding the remaining dehydrating agent in a dropwise manner when the 
reflux temperature is achieved, continuously carrying out a 
reflux reaction for 4-15 h after the remaining dehydrating agent is uniformly added in the dropwise manner within 2-4 h, completing the reaction, cooling to a 
room temperature, adjusting the pH to 6.5-7.0 with an alkali liquid, filtering, washing the 
filter cake by using an isopropanol 
aqueous solution with a 
mass concentration of higher than 60%, and 
drying at a temperature of 40 DEG C to obtain the 
isopropyl alginate. According to the present invention, with the 
isopropyl alginate preparation method, the esterification degree of the prepared isopropyl alginate is higher than 65% and is significantly higher than the esterification degree of the 
straight chain alkanol ethyl alginate prepared by using the existing technology.