  This paper deals with the following nonlinear perturbed fractional Laplacian
equation $$(-\Delta)^s u =
K(|y'|,y'')u^{\frac{N+2s}{N-2s}\pm\epsilon},\,\,u>0,\,\,u\in
D^{1,s}(\mathbb{R}^N),$$ where $0<s<1, N\geq 4,$ $(y',y'')\in
\mathbb{R}^2\times \mathbb{R}^{N-2},$ $\epsilon>0$ is a small parameter and
$K(y)$ is nonnegative and bounded. By combining a finite reduction argument and
local Pohozaev type of identities, we prove that if $N\geq
4,\max\{\frac{N+1-\sqrt{N^{2}-2N+9}}{4},\frac{3-\sqrt{N^{2}-6N+13}}{2}\}<s<1$
and $K(r,y'')$ has a stable critical point $(r_0, y_0'')$ with $r_0>0$ and
$K(r_0, y_0'')>0,$ then the above problem has large number of bubble solutions
if $\epsilon>0$ is small enough. Also there exist solutions whose functional
energy is in the order $\epsilon^{-\frac{N-2s-2}{(N-2s)^{2}}}$. Here, instead
of estimating directly the derivatives of the reduced functional, we apply some
local Pohozaev identities to locate the concentration points of the bubble
solutions. Moreover, the concentration points of the bubble solutions include a
saddle point of $K(y)$.
