  In this paper, we investigate the following critical elliptic equation $$
-\Delta u+V(y)u=u^{\frac{N+2}{N-2}},\,\,u>0,\,\,\text{in}\,\R^{N},\,\,u\in
H^{1}(\R^{N}), $$ where $V(y)$ is a bounded non-negative function in $\R^{N}.$
Assuming that $V(y)=V(|\hat{y}|,y^{*}),y=(\hat{y},y^{*})\in \R^{4}\times
\R^{N-4}$ and gluing together bubbles with different concentration rates, we
obtain new solutions provided that $N\geq 7,$ whose concentrating points are
close to the point $(r_{0},y^{*}_{0})$ which is a stable critical point of the
function $r^{2}V(r,y^{*})$ satisfying $r_{0}>0$ and $V(r_{0},y^{*}_{0})>0.$ In
order to construct such new bubble solutions for the above problem, we first
prove a non-degenerate result for the positive multi-bubbling solutions
constructed in \cite{PWY-18-JFA} by some local Pohozaev identities, which is of
great interest independently. Moreover, we give an example which satisfies the
assumptions we impose.
