The China Adolescents Science & Technology Innovation Contest (CASTIC) is China’s largest and most prestigious nationwide STEM competition for school-aged students. It encourages original research, engineering design, and creative problem solving in fields such as physics, chemistry, biology, environmental science, computer science, engineering, and more. Projects typically include research reports, prototypes, or inventions that address real-world scientific and technological challenges. CASTIC is organized by the China Association for Science and Technology (CAST), the Ministry of Education, and several national agencies, and functions as a major platform for discovering and supporting young STEM talent. Participants usually qualify through school, municipal, and provincial contests before reaching the national round. While it is primarily aimed at Chinese students from elementary through high school, the contest also invites international student teams and serves as a pathway for Chinese students to international fairs like Regeneron ISEF. Benefits include expert feedback from scientists and engineers, national recognition, and opportunities for scholarships, exchanges, and further research development.