Objective To evaluate preterm infants' growth retardation rate,and analyse its related factors during different periods. Methods From sepetember 2011 to December 2012,data of 191 premature infants in our hospital NICU were collected,including hospitalization and growing of postdischarged. Results 1)By evaluated weight,IUGR,EUGR,corrected gestational age to 48 weeks,corrected gestational age to 6 months growth retardation rate were 19.4%,32.5%,24.7%,16.0%.The differences were statistically significant.2)By discharge weight,gestational age,birth weight<P₁₀,PN,the first application of PN day age,the duration of PN were the most influencing factors to extrauterine growth retardation(EUGR) group.3)By weight of corrected gestational age of 6 months,discharge weight <P₁₀,was the most influencing factor to growth retardation group. Conclusion IUGR and EUGR management should be strengthened;nutritional support treatment should be provided in different period of preterm infants.