Molecular chaperone ZmBiP1 gene were identified and characterized in maize "Han21" line. The quantitative RT-PCR analysis indicated that ZmBiP1 gene had different expression patterns in different organs. It was highly expressed in ovaries. ZmBiP1 showed an up-regulated expression under mannitol conditions and down-regulated expression under NaCl conditions. Overexpression of ZmBiP1 in Arabidopsis led to sensitivities to salt and mannitol stresses in seed germination periods. The results suggested that ZmBiP1 gene may be a negative regulator in stress signaling pathways.