Abstract: Two hypotheses of controlling flower_bud initiation by hormonal signal in fruit trees are briefly reviewed in this paper. From the comparisons, it seemed appropriate to deduce that auxins from seeded fruits or shoot tips could be an inhibiting signal for flower_bud initiation, and high concentration of cytokinins in vegetative buds could stimulate flower_bud initiation via the weak auxin_signal. However, it remains controversial whether gibberellins themselves represent the signal or they are only involved in generating the other signal. Thus, further investigation is needed to elucidate the mechanism of controlling flower-bud initiation by hormonal signals.