This study explores counseling volunteers’ ethical judgment and behavior across the Taiwan Strait. A self-compiled questionnaire was used to survey 232 "voluntary Teacher Chang" in Taiwan and 110 "voluntary Teacher Tao" in Nanjing. The results found that: (1) Regarding ethical judgment:counseling volunteers in both places generally judged the ethical items related to confidentiality, professional responsibility, and ability, etc. Among the 18 items were judged to be unethical, 12 involved dual relationships, 3 items related to informed consent, 2 items related to confidentiality, and 1 item related to professional ability. In addition, more than half of the items with high confidence level involved dual relationships, followed by confidentiality; while the items with low confidence level and conflicting opinions also mainly involved dual relationships, followed by professional abilities and responsibilities.(2) Regarding ethical behavior: Among the 19 behaviors that were the least common among counseling volunteers in both places, 15 were dual relationships, 3 were professional abilities and responsibilities, and 1 involved confidentiality. There is one ethical behavior that is the most common among volunteer counselors in both places involves self-disclosure; " A discrepancy between ethical behavior and ethical judgment was found in 17.2% of the items for "Teacher Chang" and 19.0% for "Teacher Tao." The study points out that youth counseling hotline agencies on both sides of the Taiwan Strait need to strengthen ethics training for volunteers in dual relationships, confidentiality issues, professional competencies, and counseling of minors, and both need to have a more precise definition of whether various dual relationships are ethical. Specific recommendations were made to address the differences in ethical judgments and ethical behaviors among volunteers between the two groups.