In this paper，three hot water pre-extraction H-factors (0，500 and 1 000) and applicable digestion effective alkali dosages (15 %，18 % and 21 %) were selected to obtain bamboo kraft pulps with similar Kappa number (20). The effect of hot water pre-extraction on the elemntal chlorine free（ECF）bleaching performance of bamboo pulp was studied，through comparing brightness，post color (PC) number，decreasing rate of Kappa number，viscosity of bleached pulp with same brightness (85 %ISO) and beating degree (45°SR) under different dosages of chlorine dioxide and hydrogen peroxide. The results indicate that hot water pre-extraction before kraft pulping could obtain higher decreasing rate of Kappa number，higher brightness，lower PC number，similar viscosity of bleached pulp at the same total active chlorine factor.For the same brightness bleached pulp (85 %ISO)，hot water pre- extraction could save 1.4 % bleaching chemical，but the PC number was slightly higher.