Mires have the important ecological and environment functional, the reclamation of mires in the Sanjing plain have affected greatly the region ecological balance and climate conditions. The soil moisture and temperature have changed greatly after reclamation of mires, the rising of soil temperature and the changes of oxidation-reduction conditions increase the decomposition of the soil organic matter and soil respiration. The contents of soil organic carbon and nitrogen decrease largely with the reclamation of mires, and change greatly during early 5~7 years, then the lose of soil organic carbon show the characters of slow changes. The soil bulk specific density specific gravity increase because short of the soil organic matter after reclamation which show the characters as same as the soil organic carbon lose.