The invention discloses a preparation method of a pH-responsive carrier, a drug delivery system and a preparation method of the drug delivery system. The preparation method of the pH-responsive carrier comprises the following steps: preparing a hydrazine hydrate solution, a rice bran polysaccharide solution, a polylactic acid solution, an N,N-dicyclohexylcarbodiimide solution and a 4-dimethylaminopyridine solution; adding the hydrazine hydrate solution into the rice bran polysaccharide solution, and performing reaction to generate a rice bran polysaccharide-hydrazine hydrate intermediate; diss...
