Abstract: The influences of different physical and chemical properties(conductivity,pH value,volume weight,1 to 5mm particle diameter proportion,available Fe and Mn contents,absorptive and retainable water content,specific weight,and total porosity) of matrix in floating system on the germination rate of flue-cured tobacco seed were studied,and the correlation between germination rate and these properties were analyzed with stepwise regression.The results showed that:1) the 10 tested factors could basically reflect the effects of physical and chemical properties of matrix on germination rate;2) the hygroscopic property of matrix was the most important factor affecting germination rate,and its influence to germination rate mainly depended on direct effect,which gradually increased with the advance of germination;3) hydroscopicity,volume weight,absorptive and retainable water content,total porosity positively correlated with germination rate,the order of degree of correlation was hydroscopicity> total porosity> volume> weight absorptive and retainable water content;4) conductivity,pH value and available Mn content negatively correlated with germination rate,while these factors affected germination rate at different time,conductivity before and in the middle of germination,pH value at the beginning of germination,and available Mn in the middle and late of germination.