Abstract: In order to study the effect of soybean soluble dietary fiber(SSDF) with different molecular weight on pasting and rheological of rice starch(RS),rapid visco analyzer(RVA),rheology were employed to investigate the effect of soybean soluble dietary fibers with molecular weight of 27.8 ku for HSSDF and of 9.3 ku for LSSDF. Results of RVA indicated that HSSDF increased the peak and final viscosity of RS,while LSSDF decreased the final viscosity of RS and had no obvious change in peak viscosity. Both of them increased initial pasting temperature but decreased the values of breakdown and setback of RS. Dynamic rheological studies suggested that the addition of SSDF considerably decreased the values of storage modulus of RS. In static rheological studies,adding HSSDF increased consistency coefficient K of RS,both of these two different SSDF shortened lag ring area and fluid index n of RS pastes,made the system more stable. Studies have shown that different molecular weight SSDF,especially the HSSDF,had a significant impact on the RS pasting and rheological properties. This paper could provide certain theoretical basis for application of SSDF in rice products.