Abstract: In order to obtain high bacterial cellulose(BC)-producing strain,composite mutagenesis of ultraviolet and diethyl sulfate was used to Gluconacetobacter xylinus BC13 which preserved in laboratory. A high-yield mutant strain Y19-11, BC yield reached 15.6g/L, was obtained by mutagenesis, screening and continuous passage. The mutant strain had excellent genetic stability and its BC yield increased by 44.4%,higher than the original strain. Meanwhile,through comparing the cell weight and yield of BC under different temperature and initial pH value,the optimal temperature and initial pH of mutant strain Y19-11 were determined as 30℃ and 5.5,respectively.