Objective To analyze the physical development and parenteral nutrition status of preterm infant in a hospital in order to provide reference for the formulation of reasonable parenteral nutrition treatment plan for medium preterm infants. Methods The clinical data of 50 preterm infants aged 32～33⁺⁶ weeks from October 2017 to December 2018 were collected and analyzed retrospectively. Results The average birth weight, body length and head circumference of the child patients were (1.84±0.24) kg, (42.92 ±2.16) cm, (29.77±1.20) cm respectively. After one week and After two weeks,the average birth weight, body length and head circumference were(1.83±0.24) kg, (43.28±1.95) cm, (29.97±1.32) cm respectively and (2.07±0.23) kg, (43.91±1.79) cm, (30.62±1.13) cm respectively. The initial dose of amino acid(1.11±0.37)g·kg^-1·d^-1, fat emulsion(0.78±0.22)g·kg^-1·d^-1, glucose(5.86±1.51)mg·kg^-1·min^-1. The average days of parenteral nutrition treatment were(22.8±6.46)d, the average weight loss was(7.22±3.82)% and the average days of recovery to birth weight were (8.3±2.72)d. Conclusion The design of parenteral nutrition for preterm infants still needs to be improved in order to control the degree and duration of physiological weight loss of preterm infants in the mid-term, which is conducive to the physical development of preterm infants in the mid-term.