The  study  aimed to obtain the optimum conditions for the synthesis of zeolite A from the rice husk ash． ［Method］The  reaction temperature ，alkali concentration ，reagent  silicon and aluminum ratio and reaction time in the  synthesis of  zeolite A from rice  husk  ash  by  the hydrothermal treatment were  studied by  hydrothermal method． ［Result］Under the  conditions as the  hydrothermal  temperature  of  100 ℃ ，NaOH concentration of 2 mol / L，raw material silicon and aluminum ratio of 1－2 and reaction time of 4－6 h ，the zeolite A with higher crystallinity  could be obtained． ［Conclusion］The technology was simple and economical ，and provided a new approach to the comprehensive utilization of  bio-ash ，which is in favour of  achieving complete biomass energy  utilization system and forming the  sustainable development．