The third echelon. According to the "Implementation Opinions of Shanghai Municipal Government on the Pilot Construction of Compulsory Education Schools in the City", Shanghai schools are divided into three categories: first-line echelon, second-line echelon and third-line echelon, and the third-line echelon includes new rural schools and suburban schools. Xu Jing primary school belongs to suburban schools, so it belongs to the third echelon.