Objective To explore very low and extremely low birth weight children by three different methods of nutritional evaluation of nutritional assessment,explore the ideal nutrition for premature children evaluation methods. Methods A total of 84 VLBWIs and ELBWIs were collected.They were divided into two groups according to the length of their days receiving PN.General clinical data of birth weight,head circumference,height,and weight variance (measured once per day) were recorded.Comparisons were made among the three parenteral and enteral nutrition methods (Mounla's method,the Chinese criteria of VLBWI's growth assessment,and Christensen's weight growth chart),while using them to analyze the nutrition conditions of each group. Results Applying the Mounla's method of nutrition assessment,there were no significant difference (P>0.05) in elements and intake amounts of nutrition between the two groups.while according to the domestic preterm low birth weight child growth assessment methods,average weight growth were both more than 15 g/(kg·d).And there were significant differences(P<0.05) between the two groups.Compared weight growth chart of two groups with Christensen's,five weight growth indicators were found all behind the growth of Christensen's value,the Group 2 was more apparentent. Conclusions The conclusion of applying Mounla nutrition evaluation method and standard of the intrauterine growth rate to assess the nutrition composition of VLBWIs and ELBWIs is not comprehensive with the results found in this study,and growth curve of Christensen are uncertain for use in chinese baby.a more reasonable method of nutritional assessment and the establish of VLBWI and ELBWI growth curve needs expanding samples for further study.