It takes native cassava starch as raw material,epichlorohydrin as crosslinked agent,octenyl succinic anhydride as esterifying agent,used with wet process for synthesis crosslinked starch,octenyl succinic anhydride modified starch and crosslinked octenyl succinic anhydride modified starch.The basic surface activity of NS,CS,OSAS and COSAS,which is calcium ion tolerance,critical solution temperature(Krafft point),foaming ability,foam stability,and the emulsifying activity of plant fats and mineral oil were ex...