Objective To study the effect of collagen combined with sodium hyaluronate composite solution on the severity of transverse neck lines in patients with neck wrinkles. Methods A total of 84 patients with neck wrinkles admitted to our hospital from November 2023 to October 2024 were selected as the research subjects, and they were divided into the control group and the study group by the random number table method, with 42 patients in each group. The control group was injected with sodium hyaluronate composite solution on the basis of conventional treatment, and the study group added collagen on the basis of the control group. The Allergan transverse neck lines score, overall improvement, adverse reaction rate and satisfaction were compared between the two groups. Results The Allergan transverse neck lines scores of the study group at 1 and 3 months after treatment were better than those of the control group (P <0.05). The overall improvement rate of the study group was better than that of the control group (P <0.05). The incidence of adverse reactions in the study group was 7.14%, which was lower than 28.57% in the control group (P <0.05). The satisfaction rate of the study group was 80.95%, which was higher than 57.14% in the control group (P <0.05). Conclusion In the treatment of neck wrinkles, collagen combined with sodium hyaluronate composite solution for injection has better aesthetic improvement effects and higher patient satisfaction, with good safety.