In this paper we consider a periodic 2-dimensional quasi-geostrophic equations with subcritical dissipation. We show the global existence and uniqueness of the solution ∈ ([0, T], 1−2 a, (T 2 )) for small initial data in the Lei-Lin-Gevrey spaces 1−2 a, (T 2 ). Moreover, we establish an exponential type explosion in finite time of this solution.