  In this paper, we shall prove the $L^{p}$ endpoint decay estimates of
oscillatory integral operators with homogeneous polynomial phases $S$ in
$\mathbb{R} \times \mathbb{R}$. As a consequence, sharp $L^{p}$ decay estimates
are also obtained when polynomial phases have the form $S(x^{m_{1}},y^{m_{2}})$
with $m_1$ and $m_2$ being positive integers.
