We prove the asymptotic formula for the fourth moment of automorphic $L$-functions of level $p^{ u}$, where $p$ is a fixed prime number and $ u rightarrow infty$. This paper is a continuation of work by Rouymi, who computed asymptotics of the first t
hree moments at prime power level, and a generalization of results obtained for prime level by Duke, Friedlander & Iwaniec and Kowalski, Michel & Vanderkam.
