Abstract: The chemical stability of 3 categories of most commonly applied plant growth regulators solutions in plant tissue culture, i.e., NAA, IBA and KT solutions under different storage conditions was studied. The results showed that:In any cases, water solutions of the 3 categories of plant growth regulators would decompose gradually. So, for the accuracy of the experiments, the water solutions can be stored for not more than 10 days.The temperature and light conditions had no affect on the stability of NAA water solution. But the mother solution of IBA must be stored in darkness to keep the stability, and the mother solution of KT must be stored under conditions of low temperature and in darkness.95% of alcohol solvent could greatly improve the stability of KT and IBA mother solutions compared with water solvent. Therefore, 95% of alcohol ought be applied as solvent to prepare mother solutions for KT and IBA plant growth regulators for a longer time storage.