Abstract: Gibberellic acid (GA), indoleacetic acid (IAA), abscisic acid (ABA) and ethylene affect the elongation of rice stem (or internode). Among them, GA plays the most significant role. GA1 is the crucial factor that induces stem elongation, and GA3 has acted on as the most common exogenous hormone stimulating internode elongation of rice. Rice stem elongation is controlled both by the hormone levels and the sensitivity of stem tissue to the hormones. A change of either part will result in variation of plant hight. GAs promote plant stem to elongate so vigorously probably because GAs cause cell division and stimulate cell wall relaxation, whereas IAA mainly promotes cell wall elongation. Great progress has been made in the mol ecular mechanism of plant hormone stimulating rice stem elongation and it is expected that a new breakthrough in this field will be made in the coming years.