We consider a class of quasilinear Schrödinger equations of the form
$-\Delta u-\frac{\kappa u}{2}(1+u^2)^{-\frac{1}{2}}\Delta(1+u^2)^{\frac{1}{2}}=\lambda |u|^{p-2}u,\ x\in\Omega,$where $u\in H_{0}^{1}(\Omega),$\kappa\in (-2,0)\cup (0,+\infty),\ 2\leq p<2^*,\ N\geq 3$ and $\Omega$ is a bounded domain. By using variational approaches, we establish the existence of a solution $(\lambda, u).$ Particularly, we give the accurate $L^{\infty}$ estimate. For instance, if $\kappa\in (-2,0)$ and $|u|_{p}=1,$ we construct the following $L^{\infty}$ estimate of the solution
$ |u|_{\infty}\leq 2^{\frac{3}{2}+\frac{3}{2a}}(\kappa+2)^{-\frac{1}{2}-\frac{1}{2a}}(\lambda_{1}C_{N})^{\frac{1}{2a}}|\phi_{1}|_{p}^{-\frac{1}{a}}|\Omega|^{\frac{1}{p'}}, $where $a=\frac{1}{p}-\frac{1}{2^*},p'=\frac{p}{p-1},$C_{N}$ is the best Sobolev constant and $\lambda_{1}$ and $\phi_{1}$ are the first eigenvalue and the first eigenfunction of the operator $-\Delta$ respectively.