In this paper, we study the Kirchhoff equation with Sobolev critical exponent \begin{document}$ -\left(a+b\int_{ {\mathbb{R}}^3}|\nabla u|^2\right)\Delta u = \lambda u+\mu|u|^{q-2}u+|u|^{4}u\ \ {\rm in}\ {\mathbb{R}}^3 $\end{document} under normalized constraint$ \int_{ {\mathbb{R}}^3}u^2 c^2, $where a, \, b, c>0 are constants, \lambda, \mu\in{\mathbb{R}} and 2<q<6 $\end{document}. The...