The present invention provides a plant growth regulator having effects on the increase of yield, the increase of a function leaf, growth promotion, etc. of Musaceae plant, particularly banana, and a method of using thereof. The plant growth regulator comprising isoprothiolane (diisopropyl 1, 3-dithiolan-2-ylidene malonate) as an active ingredient and having an effect on the increase of yield of Musaceae plant, particularly banana a method of using the regulator by a spray or apply treatment, a soil-drenching treatment, or an injection treatment and a method of regulating plant growth.
