Rice protein and moisture content are pivotal in the gelatinization and retrogradation processes of rice starch. This study aimed to explore the influence of rice protein on these processes by preparing rice starch gels with varying moisture levels and incorporating rice protein. At a high moisture content of 1:6, rice protein exhibited a minimal effect on the gelatinization properties of rice starch but significantly retarded the retrogradation of the starch gel. At intermediate moisture levels of 1:4 and 1:2, the rice starch gels showed pronounced retrogradation. However, rice protein was effective in inhibiting this retrogradation at a 1:4 moisture content, while its inhibitory effect diminished at a 1:2 moisture content. Under low moisture conditions of 1:1, the gelatinization of rice starch was markedly constrained by the limited water availability, but rice protein mitigated this constraint. Conversely, at this moisture level, rice protein promoted the retrogradation of the rice starch gel during the retrogradation process. The findings of this study offer a theoretical foundation that could inform the production of rice-based products.