【Objective】This study aims to analyze the molecular mechanisms underlying flower color formation in Althaea rosea. we identified differentially expressed key genes in the anthocyanin biosynthesis pathway of A.rosea, thereby revealing the molecular basis for flower color formation, and providing genetic resources for flower color improvement in A. rosea.【Methods】We utilized red and white petals of A.rosea as test materials. The color phenotypes were quantified using a colorimeter, while anthocyanin content was assessed through biochemical analysis. Concurrently, differentially expressed genes in the anthocyanin biosynthetic pathway were identified through transcriptome sequencing, with subsequent validation performed via real-time quantitative PCR.【Results】（1）The red petals of A.rosea exhibited significantly higher‘a value’（Phenotypic data representing differences in petal color） than the white petals, indicating a significant phenotypic difference between the two petal colors.（2）The anthocyanin content in the red petals was significantly greater than that in the white petals. Correlation analysis confirmed a significant positive relationship between petal color and anthocyanin content in A.rosea.（3）A total of 2 118 differentially expressed genes were identified in the comparison between red and white petals, with 1 294 genes up-regulated and 824 genes down-regulated, and a greater number of up-regulated genes were associated with the red petals. Among these, 5 differentially expressed structural genes and 19 regulatory genes were found to be significantly related to anthocyanin biosynthesis. 6 differentially expressed genes were selected for RT-qPCR validation, and their expression trends were consistent with the transcriptome sequencing results.【Conclusion】The red coloration of A.rosea petals is attributed to the biosynthesis and accumulation of anthocyanins, which are significantly associated with 24 differentially expressed genes. Thus, we propose that these 24 differentially expressed genes may serve as key determinants of the red pigmentation observed in A.rosea petals.