Abstract: 【Objective】Compared the starch properties between two japonica rice with significant diffrences in resistant starch. 【Method】Using japonica rice lines，jiangtangdao 1 which cultivated by Shanghai Academy of Agricultural Sciences and jinfeng, with significant diffrences in resistant starch content, Compared the amylopectin chain length distribution, characters of RVA properties and differences in the molecular structure between them. 【Result】For the jiangtangdao 1 starch, short-chain portion was significantly lower than the relative rate of Jinfeng, while the relative proportions of long-chain portion was significantly higher; the peak viscosity、 hot paste viscosity and breakdown viscosity,was significantly or very significantly lower, but the setback viscosity was significantly higher than Jinfeng; jiangtaodao 1 starch is more thermostable and the crystals type is primarily for B-type crystals or B, V mixed crystal, while the Jinfeng starch is mainly A-type crystals and A, V mixed crystal.【Conclusion】The amylopectin chain length distribution, characters of RVA properties, amylose content and molecular structure of starch shows significant diffrences between high and low resistant starch content strains.Therefore,it could be used as a breeding index.