Objective:To evaluate the quality, content and feasibility of health information on breast cancer treatment in Chinese websites, for reference in standardizing online health information.Methods:In January 2022, three Chinese search engines, namely Baidu, Sogou and Haosou, were used to search with " breast cancer" and " breast cancer treatment" as keywords. The first 50 links identified by each engine were accessed to screen breast cancer treatment health information websites. Subsequently, the DISCERN scoring tool was adopted to evaluate the quality of health information on the websites(16 items). The information content(10 items)assessment was conducted by referring to the " Guidelines and Specifications for Breast Cancer Diagnosis and Treatment of the Chinese Anti-Cancer Association(2019 Edition)". The feasibility of website health information was evaluated with Patient Education Materials Assessment Tool(PEMAT).Results:A total of 19 websites were included, and their service mode was mainly active information service(14 websites). The overall scoring for the quality of health information about breast cancer treatment was 2.0, with the highest score of " clarity of purpose" (3.4). According to the assessment results of information content, these websites were divided into 4 grades: excellent(3), good(11), fair(3), and poor(2). All the websites contained the information on clinical manifestations, etiology, examination and treatment of breast cancer. The overall feasibility of website health information was 44.5%, indicating incomplete feasibility.Conclusions:The Chinese website′s health information on breast cancer treatment is poor in quality and implementation. Hence, it′s urgent to further improve and standardize online health information, establishing a unified evaluation standard and actively exploring the new mode of " Internet+ Medical" service.