Abstract: Aiming at development of transformation methods for alkalophilic Bacillus pseudofirmus JCM 9141 (growth at pH>10), screening conditions of transformants by using antibiotics were first examined to overcome the antibiotic inactivation at high pH. Then, different transformation methods including competent cells, protoplast and electroporation were studied, respectively. The transformation efficiencies of competent cells and protoplast were low, while a modified electroporation method achieved higher transformation efficiency under 3000 V•cm^-1. This method was also applicable to other alkalophilic Bacillus sps.