[Objective]The objective of the study was to reveal the several factors influencing flowering of test-tube plantlets cultured in vitro of Rhododendron hybridum.[Method] With the shoots culture in vitro as explants,the factors influencing the flowering such as medium,phytohormone,physiological state of explants,illumination,activated carbon were investigated.[Result] The 1/2 Read medium with 2.0 mg/L IBA,0.7%agar,0.2%activated carbon was suitable for inducing flower buds and the mean induction rate was 34.44...