Abstract: With the development of biogas projects,a massive amount of fermentation residues has been produced in the rural areas of China. Hence how to recycle those residues and what their potential values are have attracted great interests from both scientists and engineers. Biogas slurry is supposed to be applied as fertilizer in rice cultivation. To explore effects of soaking rice seeds with biogas slurry on seed germination and growth of rice seedlings,rice seeds（ Oryza sativa）were soaked separately in biogas slurries different in concentration for 24 h before the seeds were sown into seed beds for germination,and germination rates and seedling growth was monitored for comparison between treatments different in concentration of biogas slurry used in soaking. Results show that in the treatment using 2% of biogas slurry,the seedlings increased their root number and shoot biomass,but decreased their root biomass. However,this treatment did not have much effect on seed germination rate and speed,shoot length,shoot diameter and root length of the seedlings. Treatments higher in biogas slurry concentration inhibited both seed germination and seedling growth. As the effect of biogas slurry on root was higher than on shoot,the seedlings in all the treatments had higher shoot / root biomass ratios than CK. Analysis of respiration rate of rice seedlings reveals that treatment of rice seeds with biogas slurry may have some negative impacts on germination of seeds at the late stage. So mechanism of biogas slurry affecting seed germination and seedling growth could be complicated. As a conclusion,it is recommended that cautions be taken in using biogas slurry to treat seeds in the early stage of rice cultivation.