OBJECTIVE：To explore the effects of enteral nutrition powder in children with phenylketonuria（PKU）under one year. METHODS：120 PKU children under one year were selected and given enteral nutrition powder（20 g/kg，qd）for consecutive 32 weeks. The level of benzene，height，weight，head circumference，IQ level，nutrition indicators and ADR were compared before treatment，8 weeks after treatment，32 weeks after treatment. RESULTS：8 and 32 weeks after treatment，the level of benzene decreased gradually，and height，weight and head circumference increased gradually，with statistical significance（P＜0.05）. IQ level of children after 8 weeks treatment were better than before，and those of children after 32 weeks treatment were better than after 8 weeks treatment，with statistical significance（P＜0.05）. 8 and 32 weeks after treatment，nutrition indicators were improved significantly， compared with before treatment；ALT，Alb and TP levels 32 weeks after treatment were significantly better than 8 weeks after treatment，with statistical significance（P＜0.05）.There was no statistically significant difference in BUN，TBil and Pa levels between 32 weeks after treatment and 8 weeks after treatment（P＞0.05）. 66 cases suffered from 181 times of ADR，mainly including 10 times diarrhea and 126 times upper respiratory tract infection，among which one children developed moderate gastroenteritis. They were all recovered after symptomatic treatment. CONCLUSIONS：For PKU children under one year，enteral nutrition powder can effectively control the phenylalanine levels，prevent the decrease of IQ and improve the nutritional status so as to meet the normal growth and development of children nutritional requirements，with better safety and tolerance.