Numerical modeling of Juratype (detachment) folds by using the finitedifferent code FLAC shows that interlayer cohesion contrasts and overlying confining pressures are key factors for development of comblike and troughlike folds, indicating controlling by interlayer competence contrast and burial depth. When folded strata are in shallow levels, interlayer competence contrast plays an important role in fold styles. Lower interlayer competence contrast will produce troughlike folds whereas higher interlayer competence contrast will lead to comblike folds. As the depth increases, the pressure gradually plays a major important role and higher overlying pressures will cause troughlike folds only. Lower interlayer competence contrast in the folded strata in the eastern part of the eastern Sichuan fold belt results in troughlike folds both in shallower and deeper levels of the cover, which are consistent with our numerical modeling results. Higher interlayer competence contrast in the western folded strata causes comblike folds in the shallower levels. However, the fold style in the deeper，lower Paleozoic cover strata in the western belt are mainly controlled by overlying pressures, and the developed fold style should be troughlike folds according to the numerical modeling results.