Objective To investigate the effects of two material forms (rice flour and whole rice grains) on the modification performance of rice by heat-moisture treatment and physicochemical properties.Methods Early indica rice is used as raw material. Rice flour and whole rice grains are subjected to heat-moisture treatment (100 ℃, 2 h) under three moisture levels (21%, 24%, and 27%). Subsequently, the basic chemical composition, surface particle morphology, crystal structure characteristics, and farinograph processing properties of samples from the two groups are characterized.Results After heat-moisture treatment, the particle dispersibility of samples in both groups decreases significantly, accompanied by obvious aggregation and fusion. All the samples maintain the typical A-type crystal structure of rice starch, with a slight reduction in crystallinity, a shift of endothermic peak toward higher temperature, and a decline in enthalpy (ΔH). After treatment, the samples exhibit decreased peak viscosity, final viscosity, breakdown and setback values, delayed occurrence of peak time, and increased gelatinization temperatures. Meanwhile, the thermal stability and anti-retrogradation capacity of starch are improved. Moisture content exerts remarkable influences on surface particle morphology, damaged starch content, crystallinity, and thermodynamic characteristics of samples, whereas its effects on gelatinization properties and gel texture are weak. Material form significantly affects the modification performance of heat-moisture treatment. Compared with the rice flour group, the whole rice grain group exhibits increased amylose content, damaged starch content, characteristic particle size, gel hardness, chewiness, and resilience, as well as slightly declined starting temperature, peak temperature, ΔH, and breakdown value.Conclusion Material form significantly affects the modification performance of heat-moisture treatment on rice.