principle result for quasilinear SPDE with obstacle and even very few results in the deterministic case. The aim of this paper is to obtain, under suitable integrability conditions on the coefficients, $L^p$-estimates for the uniform norm (in time and space) of the solution, a maximum principle for local solutions of equation and comparison theorems similar to those obtained in the without obstacle case in [@DMS05; @DMS09]. This yields for example the following result:

Let $(M_t)_{t\geq 0}$ be an Itô process satisfying some integrability conditions, $p\geq 2$ and $u$ be a local weak solution of the obstacle problem (\[SPDEO\]). Assume that $\partial{\ensuremath{\mathcal O}}$ is Lipschitz and $u\leq M$ on $\partial{\ensuremath{\mathcal O}}$, then for all $t\in [0,T]$: $$E\left\| \left( u-M\right)
^{+}\right\| _{\infty ,\infty ;t}^p\le k\left( p,t\right)
\mathcal{C}(S, f, g, h, M)$$ where $\mathcal{C}(S, f, g, h, M)$ depends only on the barrier $S$, the initial condition $\xi$, coefficients $f,g,h$, the boundary condition $ M$ and $k$ is a function which only depends on $p$ and $t$, $\Vert \cdot \Vert
_{\infty ,\infty ;t}$ is the uniform norm on $[0,t]\times {\cal
O}$.

Let us remark that in order to get such a result, we define the notion of [ local solutions]{} to the obstacle 