The E.coli-B.subtilis expressional shuttle vector(pYG43) with a strong promoter P43 was constructed. It can make β-galactosidase gene efficiently expressed(up to 9200U)in E.coli DH5α. Alkaline cellulase was secreted(up to 60U/ml)in B.subtilis 1A747 using it, which activity was enhanced 5~7 times than the host strain.