To develop the potential use as new host strain for gene cloning the optimal conditions for transform-ation of alkali-tolerant Bacillus sp. were examined. The Bacillus sp. YA-14 was cultured to late logarith-mic growth phase at 37$^{circ}C$ in modified SPI medium (pH8.0) containing 0.4% MgSO4 0.5mM CaCl2 1 ml of competent cell was mixed with 0.5$mu$g of plasmid DNA and incubated with shaking at 37$^{circ}C$ for 40min. The transformation frequency under the optimal condition was 4.53$ imes$10-6 CFU/ml/g plasmid DNA. The electrophresis and stably maintained in the new host.