Objective:To assess the characteristics and correlation of motor development in preterm infants of different gestational weeks by using the Test of Infant Motor Performance (TIMP) method, and to develop better individualized early interventions based on TIMP test results.Methods:A prospective study involving 43 full-term healthy infants and 77 preterm followed up in 3201 Hospital from June 2019 to July 2021 was conducted.Preterm infants were divided into the early preterm group (39 cases) and late preterm group (38 cases) according to their gestational age at birth.TIMP assessment was performed at the gestational age of 40 weeks and the corrected age of 16 weeks after birth.Similarly, the full-term healthy infants were assessed by TIMP at the postnatal age of 16 weeks.The differences between groups were investigated using ANOVA or Mann- Whitney rank sum test.Correlations were analyzed by the Pearson correlation method. Results:There were no significant difference in TIMP scores between early and late preterm infants at the gestational age of 40 weeks [(65.74±6.52) scores vs.(66.96±8.51) scores] and the corrected age of 16 weeks [(101±10) scores vs.(104±8) scores] (all P>0.05). TIMP scores in the full-term healthy group at the corrected age of 16 weeks [(108±10) scores] differed significantly from those of early and late preterm infants ( P<0.05). Compared with full-term infants, early and late preterm infants had lower TIMP scores in observation, supine position, and supine turning (all P<0.05), but a higher TIMP score in standing position ( P<0.05). For both early and late preterm infants, TIMP scores at the gestational age of 40 weeks were significantly positively correlated with those at the corrected age of 16 weeks ( r=0.565, 0.302, all P<0.01). Conclusions:There were significant differences in motor development between preterm infants of different gestational ages and term infants, which had guiding significance for early intervention.English version TIMP could play a positive role in promoting individualized follow-up and early intervention of preterm infants in China.