  Let $f$ be a holomorphic cusp form of even weight $k$ for the modular group
$SL(2,\mathbb{Z})$, which is assumed to be a common eigenfunction for all Hecke
operators. For positive integer $n$, let $\text{Sym}^n(f)$ be the symmetric nth
power lifting of $f$ , which was shown by Newton and Thorne to be automorphic
and cuspidal. In this paper, we construct certain auxiliary $L$-functions to
show that Siegel zeros of $\text{Sym}^n(f)$ do not exist, for each given $n$,
utilizing the above functoriality result. As an application, we give a lower
bound of those symmetric power $L$-functions at $s=1$ of logarithm power type.
