Abstract: The amylose and amylopectin were separated from jackfruit seed starch(JFSS). Malaysia(M1)amylose was mixed 1:1 with amylopectin of M1,Malaysia(M5),Malaysia(M6),Malaysia(M11)and Xinglongbendi(BD),respectively,to prepare gelatinized JFSS(GJFSS:M1',M5',M6',M11' and BD')with different degree of amylopectin polymerization. The effects of different degree of amylopectin polymerization on the gelatinization process of JFSS were investigated by particle morphology,freeze-thaw stability,thermal properties,gelatinization properties and short-range molecular order. The results showed that BD' had the highest degree of amylopectin polymerization,followed by M11,M6,and M5 while the lowest degree of amylopectin polymerization for the M1.The five GJFSS samples showed significant variations in microstructure varying from a compact structure(M1')to a loose structure(BD'). The microstructure results showed that freeze-thaw stability was consistent. High syneresis formed a compact structure(M1'),and low syneresis formed a loose structure(BD'). As the degree of amylopectin polymerization increased,the gelatinization enthalpy,peak viscosity,trough viscosity,breakdown,final viscosity,setback,and absorbance ratios decreased while the transition temperatures and pasting temperature increased. The microstructure and syneresis results showed that thermal,pasting properties and short-range molecular order were consistent. All the results indicated that the degree of amylopectin polymerization was an important structural factor that it could significantly affect the gelatinization properties of starch.