Let m and n be two positive integers such that \(m \le n\) and \(n \ge 3\) . In this article, by the unstable K-theory method, we will study the homotopy types of gauge groups of the principal SU(n)-bundles over \(\mathbb {C}P^3\) . Let \(\mathcal {G}_{l,k}(\mathbb {C}P^3)\) be the gauge groups of the principal SU(n)-bundles over \(\mathbb {C}P^3\) , we will partially classify the homotopy types of \(\mathcal {G}_{0,k}(\mathbb {C}P^3)\) by showing that if there is a homotopy equivalence \(\mathcal {G}_{0,k}(\mathbb {C}P^3)\simeq \mathcal {G}_{0,k'}(\mathbb {C}P^3)\) then we have \((\frac{1}{2}(n-1)n(n+1)(n + 2), k)=(\frac{1}{2}(n-1)n(n+1)(n+2), k')\) , when n is odd and \((\frac{1}{4}(n-1)n(n+1)(n + 2), k) = (\frac{1}{4}(n-1)n(n+1)(n+2), k')\) , when n is even.