Based on nonlinear Kerr effect model of erbium-doped ring fiber laser, the influences of pump power and nonlinear coefficient on chaotic bandwidth are investigated. The results indicate that, with fixed nonlinear coefficient, the bandwidth of the chaos increases first and then decreases with the increasing of pump power. Fixing the pump power at 01 W, the chaotic bandwidth rises up to 153 GHz with the nonlinear coefficient increased to 45 W-1km-1. On further increasing the nonlinear coefficient the chaotic bandwidth is reduced gradually.