A method for preparing physiologically active peptide-containing microparticle comprising: 1) mixing a physiologically active peptide with an ionic water-soluble polymer in an aqueous medium to form an ionic complex of the physiologically active peptide and the water-soluble polymer; 2) drying the ionic complex of the physiologically active peptide and the water-soluble polymer obtained in step 1); 3) homogeneously mixing the ionic complex of the physiologically active peptide and the water-soluble polymer obtained in step 2) with a biodegradable, water-insoluble polymer in a non-aqueous solvent; and 4) removing the non-aqueous solvent from the resulting solution obtained in step 3) to obtain microparticle; wherein the water-soluble polymer is the compound represented by Formula 2 or 6 below: [Formula 2] RO-CHZ-[COO-CHX] p -[COO-CHY'] q -COO-CHZ-COOM wherein X is methyl group; Y' is hydrogen atom or phenyl group; p is an integer of 0 to 25 and q is an integer of 0 to 25 provided that p+q is an integer of 5 to 25; R is hydrogen atom, or acetyl group, benzoyl group, decanoyl group, palmitoyl group, methyl group or ethyl group; M is H, Na, K, or Li; and Z is hydrogen atom, methyl group or phenyl group, [Formula 6] YO-[-C - a -O-] m -C -R-C -[-O-(CHX') b -C -] n -OZ wherein each of X and X' is independently hydrogen, alkyl or aryl; each of Y and Z is independently H, Na, K, or Li; each of m and n is independently an integer of 0 to 95 provided that 5<m+n<100; each of a and b is each independently an integer of 1 to 6; and R is substituted or unsubstituted -(CH 2) k - in which k is an integer of 0 to 10, divalent alkenyl having 2 to 10 carbon atoms, divalent aryl having 6 to 20 carbon atoms, or a combination thereof; the biodegradable, water-insoluble polymer is one or more selected from the group consisting of polylactide, polyglycolide, poly(lactide-co-glycolide), polyorthoester, polycaprolactone, polydioxanone, polyalkylcarbonate, polyanhydride and copolymers thereof; the water-soluble polymer has a number average molecular weight of 500 to 5,000 daltons; and the biodegradable, water-insoluble polymer has a weight average molecular weight of 10,000 to 100,000 daltons. 1) mixing a physiologically active peptide with an ionic water-soluble polymer in an aqueous medium to form an ionic complex of the physiologically active peptide and the water-soluble polymer; 2) drying the ionic complex of the physiologically active peptide and the water-soluble polymer obtained in step 1); 3) homogeneously mixing the ionic complex of the physiologically active peptide and the water-soluble polymer obtained in step 2) with a biodegradable, water-insoluble polymer in a non-aqueous solvent; and 4) removing the non-aqueous solvent from the resulting solution obtained in step 3) to obtain microparticle; wherein the water-soluble polymer is the compound represented by Formula 2 or 6 below: [Formula 2] RO-CHZ-[COO-CHX] p -[COO-CHY'] q -COO-CHZ-COOM wherein X is methyl group; Y' is hydrogen atom or phenyl group; p is an integer of 0 to 25 and q is an integer of 0 to 25 provided that p+q is an integer of 5 to 25; R is hydrogen atom, or acetyl group, benzoyl group, decanoyl group, palmitoyl group, methyl group or ethyl group; M is H, Na, K, or Li; and Z is hydrogen atom, methyl group or phenyl group, [Formula 6] YO-[-C - a -O-] m -C -R-C -[-O-(CHX') b -C -] n -OZ wherein each of X and X' is independently hydrogen, alkyl or aryl; each of Y and Z is independently H, Na, K, or Li; each of m and n is independently an integer of 0 to 95 provided that 5<m+n<100; each of a and b is each independently an integer of 1 to 6; and R is substituted or unsubstituted -(CH 2) k - in which k is an integer of 0 to 10, divalent alkenyl having 2 to 10 carbon atoms, divalent aryl having 6 to 20 carbon atoms, or a combination thereof; the biodegradable, water-insoluble polymer is one or more selected from the group consisting of polylactide, polyglycolide, poly(lactide-co-glycolide), polyorthoester, polycaprolactone, polydioxanone, polyalkylcarbonate, polyanhydride and copolymers thereof; the water-soluble polymer has a number average molecular weight of 500 to 5,000 daltons; and the biodegradable, water-insoluble polymer has a weight average molecular weight of 10,000 to 100,000 daltons.