This paper presents for the first time the idea of constructing reconfigurable generalized parallel mechanisms (GPMs) by integrating closed-loop kinematotropic linkages with configurable platforms. This leads to a novel way of constructing reconfigurable mechanisms. The geometrical configurations of the closed-loop kinematotropic linkages are analyzed in different working phases. By assembling kinematotropic linkages to moving platforms, the reconfigurable GPMs with configurable platforms are obtained. The kinematic constraints of the reconfigurable GPMs are investigated based on the algebraic structure properties of Lie group. Then a new class of reconfigurable GPMs with configurable platforms is synthesized. The variation of the configurable platforms leads to the reconfigurability of the resulting mechanisms. Consequently, the derived mechanisms can perform several motion models associated with different working phases of the kinematotropic linkages. Finally, a five degree-of-freedom reconfigurable GPM with configurable platform is selected as the typical example to perform the kinematic position analysis. Besides, the workspace analysis of the mechanism is carried out.