Osmoconditioning and hardening effects for the seed germination of normal and naturally aged rice seeds were studied through analyzing the total sugars and $alpha$-amylase activity. The normal seeds which used to have high germination rate accelerated germination with the osmoconditioning at the suboptimal temperature of 17$^{circ}C$. On the other hand, the aged seeds did not affect germination rate at $25^{circ}C$, while increased germination rate and accelerated germination a little at 17$^{circ}C$, Hardening of aged seeds increased germination rate by 10-15% compared with control seeds at both 17 and $25^{circ}C$ and accelerated germination. Total sugar content and $alpha$-amylase activity of normal seeds were higher than did aged seeds. The aged seeds with treatment of osmoconditioning and hardening increased total sugar content and $alpha$--amylase activity, but hardening was more effective than osmoconditioning. The $alpha$--amylase activity was positively correlated with the total sugar content and germination rate.