Bamboo is a fast growing non-wood plant with long and thin fibers. Therefore, it has potential as a raw material for pulping and papermaking. In this work, the effects of alkali charge and sulfidity on the kappa number, yield and viscosity were investigated in a bamboo kraft pulping process before and after O(2)-delignification. The results indicated that higher alkali charge can get higher residual alkali and lower yield, kappa number and viscosity. Higher sulfidity can conclude higher viscosity and lower yield, residual alkali and kappa number.