To analyze the clinical effect of red and blue light combined with collagen dressing in the treatment of rosacea. Methods A total of 80 patients with rosacea admitted to our hospital from April 2021 to May 2023 were randomly divided into control group and observation group, with 40 patients in each group. The control group was treated with red and blue light, and the observation group was treated with red and blue light combined with collagen dressing. The clinical efficacy, inflammatory skin lesion score, epidermal water content, skin physiological index, quality of life and adverse reactions were compared between the two groups. Results The total effective rate of treatment in the observation group was 95.00%, which was higher than 70.00% in the control group (P <0.05). After treatment, the inflammatory skin lesion score and epidermal water content in the observation group were better than those in the control group (P <0.05). The scores of brown spots, red areas, purple and pores in the observation group were better than those in the control group (P <0.05). The scores of all dimensions of quality of life in the observation group were higher than those in the control group (P <0.05). The incidence of adverse reactions in the observation group was 5.00%, which was lower than 22.50% in the control group (P <0.05). Conclusion The effect of red and blue light combined with collagen dressing in the treatment of rosacea is ideal, which can effectively reduce the skin lesions of patients and improve their skin physiological indexes. Meanwhile, it has fewer adverse reactions and higher safety, which is conducive to improving the quality of life of patients.