  In this paper, we investigate the Cauchy problem for the higher-order
KdV-type equation \begin{eqnarray*}
  u_{t}+(-1)^{j+1}\partial_{x}^{2j+1}u
  + \frac{1}{2}\partial_{x}(u^{2})
  = 0,j\in N^{+},x\in\mathbf{T}= [0,2\pi \lambda) \end{eqnarray*} with low
regularity data and $\lambda\geq 1$. Firstly, we show that the Cauchy problem
for the periodic higher-order KdV equation is locally well-posed in
$H^{s}(\mathbf{T})$ with $s\geq -j+\frac{1}{2},j\geq2.$ By using some new
Strichartz estimate and some new function spaces, we also show that the Cauchy
problem for the periodic higher-order KdV equation is ill-posed in
$H^{s}(\mathbf{T})$ with $s<-j+\frac{1}{2},j\geq2$ in the sense that the
solution map is $C^{3}.$ The result of this paper improves the result of
\cite{H} with $j\geq2$.
