Abstract: Objective：To re-determine items difficulty order of the Fudan Chinese version gross motor function measure(GMFM), and to compare the responsiveness and precision with the GMFM-66, in order to improve the items difficulty order of the GMFM to suit children with cerebral palsy in all age groups better. Methods：The data used for the analysis in this study were from children and adolescents with cerebral palsy undergoing rehabilitation therapy and education in rehabilitation center of Children's hospital of Fudan University and other 21 cooperative units in Shanghai Children's Rehabilitation Cooperative Group from 2001 to 2017. Each one of the cases had at least one time GMFM assessment and was diagnosed as cerebral palsy after 18 months. GMFM assessment was performed by a designated therapist or physician in a quiet, independent, well-lit room using Fudan Chinese version GMFM-88.The GMFM-66 score was derived from GMAE (version 1.0). Each GMFM-88 item was converted into three sub-items, and the GMFM-88 was converted into GMFM-264 containing 264 test items, with a score point (0, 1) for each. The rating scale model in Rashi analysis was used to analyze the GMFM-264 test results and 264 items, and generate the improved Fudan Chinese GMFM scale items difficulty order.Stratified random sampling method was used to determine the subjects included in the analysis of responsiveness and precision, and the difference in the scores of GMFM-264 and GMFM-66 were used to compare the responsiveness and precision of two score methods by comparing each assessment results of the below 3-year-old group and the above 6-year-old group. Results：A total of 3 498 GMFM assessment results of 1 198 children with cerebral palsy were included in the analysis. Among them, 801 were males. The average age was (4.5±3.8) years old when they had their first assessment. Rasch analysis showed that the unsuitable items of the total items was 2.3% in GMFM-264 tiny items, indicating that most of the items in this scale have good unidimensionality and form improved Fudan Chinese version items difficulty order containing 264 tiny items. In the <3 year old group, the responsiveness and precision of GMFM-264 was significantly higher than that of GMFM-66. Conclusion：The improved Fudan Chinese GMFM items difficulty order expands the target pool for the development of gross motor intervention in children with cerebral palsy combined with standardized assessment, and improves the responsiveness and precision of GMFM in children with cerebral palsy, especially infants with cerebral palsy. The result+ provide a basic model and data for the further promotion of intelligent function assessment and intervention systems for children with cerebral palsy.