  An effective theory for the hole doped spin-1 antiferromagnetic chain is
proposed in this paper. The two branches of low energy quasipaticle excitation
is obtained by the diagrammic technique. In the large t limit(in which t is the
hole hopping term), the lower band is essentially the bound state of one hole
and one magnon and the other band is the sigle hole state. We find a critical
value of t, $t_c=0.21\Delta_H$(in which $\Delta_H$ is the Haldane gap).For
$t>t_c$, with the decrement of t, the mixing of these two bands become stronger
and stronger, and at the same time the effective band mass becomes larger and
larger. When $t<t_c$ the minimum of the lower band moves away from zero the
another point between zero and $\pi/2$. The spin strcture factor is also
calculated in this paper, and we find that for large t limit the main
contribution is from the inter-band transition which induce a resonant peak in
the Haldane gap. While for small t limit the main contribution is from the
intra-band transition which only cause a diffusion like broad bump in the
Haldan gap.
