In this paper, we consider the following anisotropic quasi-geostrophic equations \(\begin{aligned} \partial _t\theta + u_\theta \cdot \nabla \theta +\mu |\partial _1|^{2\alpha }\theta +\nu |\partial _2|^{2\beta }\theta =0,\quad u_\theta =\mathcal {R}^{\perp }\theta , \qquad \qquad (AQG)_{\alpha ,\beta } \end{aligned}\) where \(\min \{\alpha ,\beta \}=\frac{1}{2}\) et \(\max \{\alpha ,\beta \}\in \left( \frac{1}{2},1\right) \) . This equation is a particular case of the equation introduced by Ye (2019) in Ye (Nonlinearity 33:72, 2019). In this paper, we prove that for any initial data \(\theta ^0\) in the Sobolev space \(H^{s}(\mathbb {R}^2)\) , \(s >1\) , the equation \((AQG)_{\alpha ,\beta }\) has a global solution \(\theta \) in \(C_b(\mathbb {R}^+,H^s(\mathbb {R}^2)).\)