Objective To investigate the skeletal and dental contribution rate to the improvement of dental relationships along the functional occlusion plane after face mask and rapid palatal expansion (FM/RPE) treatment in Class Ⅲ patients.Methods Nineteen Class Ⅲ patients in early permanent dentition firstly were observed for 6 months and then FM/RPE treatment was applied for another 6 months.Pitchfork analysis was used to evaluate the skeletal and dental changes between these two periods.Results FM/RPE treatment made 7.9 mm molar correction in general,which included 4.2 mm skeletal change and 3.7 mm dental change.For the skeletal change,maxillary contribution was 0.7 mm while mandibular contribution was 3.6 mm.For the dental change,upper molar contributed 1.5 mm while lower molar 2.2 mm.Conclusions The treatment with FM/RPE for the Class Ⅲ patients in their early permanent dentition could get great occlusion improvement and limited skeletal change.For the molar relationship improvement,the skeletal and dental contribution ratio was nearly 1:1.And within the skeletal change,the contribution ratio of upper and lower jaw was about 1:5.Within the dental change,the contribution ratio of upper and lower molar was about 1:1.