This paper studies the existence of periodic solutions of Duffing type p-Laplace equations ${\left({\varphi }_p\left(x^{\mathrm{\prime }}\right)\right)}^{\mathrm{\prime }}+g(x)=p(t)$. When g has a singularity and satisfies one-sided non-resonant condition, we prove the existence of periodic solutions by using the phase plane analysis method and the continuation lemma.