A novel phytase gene Sphyl was isolated based on screening a cDNA library which was constructed from germinated soybean (Glycine max (L.) Merr. cv. Kefeng 6) cotyledon. The full-length cDNA of Sphyl was 1644 bp predicated to encode 547 amino acids including an N terminal signal peptide of 27 amino acids. Phylogenetic analysis indi-cated that Sphyl had high similarities with the phytase genes from Medicago truncatula and rice, and acid phosphatase genes from M. truncatula and Arabidopsis. Prokaryotic expression of Sphyl in Escherichia coli BL21 (DE3) showed that the induced protein had high phytase activities. The tran-scripts of Sphyl could be detected in various tissues, such as cotyledons, leaves, stems and roots of seedlings. The phytase activities in the above tissues were in accordance with their corresponding Sphyl transcripts. The transcripts of Sphyl in cotyledons showed an increasing trend from 5 to 30 days after germination, suggesting that Sphyl had involved the hydrolyses of the organic phosphorus compounds in seeds from the stages of early seed germination to young seedlings in soybean. Therefore, it was speculated that Sphyl played an important role during the seed germination and the growth of the seedlings by releasing inorganic phosphorus (P) from phosphorus reserve in seeds.