The present invention provides a method for analyzing agonist-activity to a cytokinin receptor, which comprises (1) bringing an examinee substance into contact with a transformed cell into which DNA coding the cytokinin receptor is introduced and (2) measuring the existence or the quantity of intracellular signal transduction from the cytokinin receptor expressed in the transformed cell, and, a method for analyzing antagonist-activity to a cytokinin receptor, which comprises (1) bringing an examinee substance and a substance having agonist-activity to the cytokinin receptor into contact with a transformed cell into which DNA coding the cytokinin receptor is introduced and (2) measuring the existence or the quantity of intracellular signal transduction from the cytokinin receptor expressed in the transformed cell, and the like.