The generalized fractional dynamical system with order lying in (0, 2) is investigated. We present the stability analysis of that system using Mittag-Leffler function, the Gronwall-Bellman Lemma and Laplace transform. The bifurcation diagram of generalized fractional-order Chen system is given. We investigate a theorem to control the chaotic generalized fractional-order systems by linear feedback control. Two examples to achieve the theorem of control are given. The synchronization between two different chaotic generalized fractional systems is presented. We give a theorem to calculate the control functions which achieve synchronization. This theorem is applied to achieve the synchronization between different generalized fractional-order systems with order lying in (0, 1]. And, also, used to achieve the synchronization between the identical generalized fractional-order L"{u} systems with order lying in [1, 2). There exist an agreement among analytical results and numerical treatments for stability, control and synchronization theorems.