Abstract: The moisture change and dimensional stability of the sympodial bamboo floor made in India and the commercial moso bamboo flooring made in China under indoor hygrothermal environment that simulated condition of winter and summer were studied in this paper. The moisture absorption change abided by the Fick rule and dimensional change of the two kind of bamboo flooring were very similar. The results showed that the equal moisture content and moisture absorption speed of the sympodial flooring were higher than that of moso bamboo flooring in summer extreme conditions. However, less differences were found in winter conditions. It was due to the differences of bamboo nature, processing treatment and flooring structure. The dimensional and moisture absorption of sympodial bamboo and moso bamboo were similar with that of Red Oak in United States.