The effects of space size on the weaning success and growth performance of juvenile yellowcheek carp (Elopichthys bambusa) were investigated.Five groups were assigned in different size net cages (length × width × height):0.5 m×0.5 m×0.6 m(S1),1.0 m×1.0 m×0.6 m(S2),1.5 m×1.5 m×0.6 m(S3),2.0 m×2.0 m×0.6 m(S4),3.0 m×3.0 m×0.6 m(S5) and each group contained three replications.The original density of fry (0.64±0.05 g) in each net cage was 500 inds m-3.The weaning success rate (WSR) increased first and then decreased with the increasing of space size,with the highest WSR in S2 and the lowest WSR in S1.The cumulative mortality rate (MR) (30~57 DAH) was highest in S5 and lowest in S3 (P＜0.05).The total cannibalism rate (CR) (30~57 DAH) increased with the increasing of space size.The specific growth rate (SGR) in S1 and coefficient of variation (CV) of body weight in both S2 and S3 were significantly lower than those in other groups (P＜0.05).The optimum size of net cage for the weaning of juvenile yellowcheek carp was 1.5 m×1.5 m×0.6 m based on the comprehensive results of WSR,weaning efficiency and manipulation strength.