To assess the contribution of ocular residual astigmatism (ORA) to anterior corneal astigmatism (ACA) in children with low and moderate myopia. Refractive astigmatism (RA) were received by subjective manifest refraction. ACA were obtained by IOL Master. Using Thibos vector analysis to calculate ORA. Correlation analysis was used to assess the relationship between the magnitude of ORA and ACA. The contribution of ORA to ACA was evaluated by Physical method. The study analyzed 241 right eyes of 241 children aged 8 to 18 years old. In this study, the median magnitude of ORA was 1.02 D, with interquartile range was 0.58 D. Against-the-rule ORA was seen in 232 eyes (96.3%). There was a significant and moderate correlation between ORA and ACA (r = 0.50, P < 0.001). The ORA in 240 eyes (99.6%) had a compensatory effects on ACA. The mean compensation value was 1.00 ± 0.41 D. Based on this effect, 37 eyes had different axial classification of ACA and RA. By contrast, one eye (0.4%) had oblique ORA and superimposed with-the-rule ACA. The magnitude of ORA was relatively huge in myopia children and predominantly compensated ACA. The ORA should be assessed first before fitting orthokeratology.