The invention relates to the technical field of children products, in particular to a multifunctional children chair frame structure which comprises a chair body and a base, the chair body comprises a supporting frame, the multifunctional children chair frame structure is characterized in that the supporting frame comprises an upper support, a connecting piece and a lower support, and the base comprises a transverse rod, a side rod, a first gear adjuster and a second gear adjuster; the transverse rod is connected with the side rod, the lower support is connected with the side rod through a first gear adjuster, the lower support is connected with the upper support through a connecting piece, the base further comprises a supporting rod, and the supporting rod is connected with the side rod in a pivoted mode through a second gear adjuster. The device is small and space-saving.