On May 11, No. 143 CIDEG Academic Salon was held in Room 302, the School of Public Policy and Management (SPPM) at Tsinghua University. LI Jin, Professor of Education and Human Development at Brown University, gave a keynote report on “The Mental Health of the Left-behind Children.” LU Mai, Secretary-General of China Development Research Foundation, member of CIDEG Academic Committee was the commentator. CHEN Ling, Associate Professor of SPPM, Deputy Director of CIDEG, moderated the Salon. Professor LI Jin stated the key influence of nurture in the growth of infants, illustrated the importance of attachment relationship, and finally discussed the solution to the problem of left-behind children from the angle of state policy.