In order to further develop and utilize the polysaccharides in tea residue, taking tea residue after green tea water extraction as raw material, and the yield of water-soluble reducing sugar was taken as the index, the effects of irradiation degradation + alkali degradation + acid degradation on green tea residue preparation of water-soluble reducing sugars were discussed on the basis of optimization of radiation degradation, alkali degradation and acid degradation for preparation of water-soluble reducing sugars. Results: The best degradation rate of irradiation was 1 200 kGy with a yield of 4.13%. The best combination of alkali degradation was 0.05 mol/L sodium hydroxide at 90 ℃ for 1 h, the yield was 2.08%. The optimal process of acid degradation was 9% nitric acid at 100 ℃ for 2 h, and the yield was 10.57%. The best combination of radiation degradation + alkali degradation + acid degradation was that the tea residue was firstly irradiated by irradiation at 1 000 kGy, degraded by the best combination of alkali degradation, and then degraded by the best combination of acid degradation, with the water-reducing sugar yield of 13.18%. The combination of degraded water-soluble reducing sugar has the highest yield.