Let \(\mathbb{k}\) be an algebraically closed field of characteristic p ≠ 2, and let Q8 be the quaternion group. We describe the structures of all simple modules over the quantum double \(D(\mathbb{k}Q_{8})\) of group algebra \(\mathbb{k}Q_{8}\) . Moreover, we investigate the tensor product decomposition rules of all simple \(D(\mathbb{k}Q_{8})\) -modules. Finally, we describe the Grothendieck ring \(G_{0}(D(\mathbb{k}Q_{8}))\) by generators with relations.