Rice (Oryza sativa L.) grain attributes, such as grain length and shape, milling quality, and physicochemical quality, are crucial for varietal development and subsequent farm adoption. Thus, it is crucial to comprehend the phenotypic range of these grain attributes and how they relate to one another. Therefore, this study analyzed the main grain quality traits in medium-grain rice, namely the amylose content (AC), gelatinization temperature (GT), gel consistency (GC), ratio of head rice (HR), and percentage of chalkiness (PC). Correlations among the major quality characteristics were then calculated through Pearson correlation matrix analysis. The results showed that AC was highly connected with GC, and PC and HR (GC) showed a strong correlation. The correlation between GT and GC was average. The other quality traits did not correlate significantly. The phenotypes of the grain quality traits provide a basis for improving the quality of medium-grain rice populations.