Objectives To analyze the effect of sling exercise therapy on the walking ability of children with spastic hemiplegia and cerebral palsy, and to provide a scientific basis for clinical treatment. Methods Children with spastic hemiplegia and cerebral palsy who were treated in the Department of Rehabilitation of Children’s Hospital of Shanghai from July 2018 to July 2019 were selected as the research subjects. The children were divided into conventional treatment group and sling exercise therapy group by random number table method. The routine treatment group was given routine rehabilitation training, and the sling exercise therapy group was given combined sling exercise therapy on the basis of routine treatment. The Gross Motor Function Measure (GMFM)-88-item E functional area score, Clinical Spasticity Index (CSI) and Berg Balance Scale (BBS) score were compared between the two groups. Results A total of 36 children were included, with 18 cases in each group. There was no significant difference in gender, age and hemiplegia side between the two groups (P>0.05). All children completed the trial without adverse reactions. Before treatment, there was no significant difference in BBS, CSI and GMFM-88 E functional area scores between the two groups (P>0.05). After 3 months of treatment, the above scores of the two groups were improved compared with those before treatment (P<0.05). The improvement of the above scores in the sling exercise therapy group after treatment was better than that in the conventional treatment group. The difference of BBS, CSI, and GMFM-88 E functional area scores in the sling exercise therapy group before and after treatment was 8.94±4.15, 2.44±0.71, and 7.28±3.23, respectively, the difference of the above scores before and after treatment in the conventional treatment group was 4.50±4.15, 1.83±0.79, and 2.89±1.64, respectively, and the differences were statistically significant (P<0.05). Conclusion Combined use of sling exercise therapy can better improve the walking ability of children with spastic hemiplegia and cerebral palsy, which is worthy of clinical promotion and application.