Objective To evaluate the myopization of astigmatism-related ametropia. Methods Case series study. Two hundred and ten children (412 eyes), 114 boys and 96 girls, aged 4 to 6 years with astigmatism were involved in the study. The children were examined 3 times over 24 months, measuring best corrected visual acuity, axial length, refraction and astigmatism after pupil dilation (with 1% atropine) and monitoring other indicators to analyze the difference between the type and degree of astigmatism. A mixed model in SAS 9.2 software program was used for analysis.Results Axial length (AXL) and spherical diopters of myopic astigmatism in ametropic children increased with the amount of astigmatism during the 24 months (F=7.380, 10.636, P＜0.01 for both).Myopia was aggravated more seriously in the group with very high amounts of astigmatism than in the mild to severe groups (P＜0.05 for all), while no significant difference was found between the mild and moderate groups. The mean values for the increased AXL and spherical amounts of myopia were (0.19±0.10)mm and (0.78±0.79)D in the mild group, (0.20±0.14)mm and (0.94±0.79)D in the moderate group, (0.33±0.14)mm and (1.36±0.68)D in the high group, and (0.38±0.12)mm and (1.60±0.58)D in the very high group. During myopic progression over the two years, the with-the-rule astigmatism group was the slowest to progress, with mean increases of (0.20±0.17)mm and (0.74±0.49)D of AXL and spherical degrees of myopia, respectively, followed by the against-the-rule group with mean increases of (0.28±0.17)mm and (1.26±0.98)D. The mean increases for the oblique group were (0.43±0.20)mm and (1.61±0.74)D, which showed the fastest myopization progress. No significant difference was found between the against-the-rule and oblique groups, but they both had significant increases in myopization (F=12.351 and 12.384, P＜0.01 for both). Conclusion This study shows that myopia progresses much faster with high and very high astigmatism than with mild to moderate astigmatism. Myopia progresses the faste