Abstract: In order to explore regulatory function of H₂O₂ in bud dormancy release, main effects of three dormancybreaking treatments (high temperature, hydrogen cyanamide and TDZ) on H₂O₂ metabolism were determined, and impacts of H₂O₂ on Ca²⁺ transport were tested using noninvasive microtest technique. The results showed that both high temperature and hydrogen cyanamide induced H2O2 accumulation and CAT inhibition were efficient in breaking dormancy during deep dormancy period. However, TDZ showed little impacts on H₂O₂ metabolism and was much less effective in breaking dormancy. Dormant floral primordium was absorbing state to exogenous Ca²⁺ due to active calcium channels. The Ca²⁺ transport could be changed by exogenous H₂O₂. H₂O₂ of low concentration reduced the absorption rate of Ca²⁺, and  at high concentration, it changed the Ca²⁺ transport direction from absorption to release. The results indicated that H₂O₂ signals were related with Ca²⁺ signals in dormant buds. Ca²⁺ signal regulated by H₂O₂ accumulation might be important in the dormancybreaking signal transduction process induced by high temperature and hydrogen cyanamide.