Objective To study morphology of the maxilary arch of the patients with non-syndromic complete unilateral cleft lip and palate in order to help assessment of clinical development of arch, occlusion and occlusal guidance therapy. Methods BR>This study included maxillary models of 32 non-syndromic complete unilateral cleft lip and palate patients. The models were scanned and measured by Denmark 3Shape Dental Model scanner and software. Length, width and circumference of both noncleft and cleft sides were measured. Spss14.0 was used to analyze the results with paired samples statistics. Results In the premolar area, there was statistical significance between width of noncleft and cleft side (first premolar areaEM> t/EM> =5.19, EM>P/EM> <0.01；second premolar area EM>t /EM>=3.24, EM>P /EM><0.05). In the first permanent molar area, there was no statistical significance between width of noncleft and cleft sides (EM> t/EM> =0.48, EM>P/EM> >0.05). The circumferences of noncleft side was longer than cleft side and the difference was 4.2 mm, which was statistically significant.( EM> t/EM> =4.611, EM>P /EM><0.01). There was statistical significance between them. Conclusion In non-syndromic complete unilateral cleft lip and palate patients, the cleft sides of maxillary arch are significantly under-developed. The circumference of cleft sides is less than n