Abstract: In order to explore the chemical regulation of the plant type dwarfing of Coleus blumei, its cutting plantlets were used as the experimental materials in this research. Through studying its height and cytological characters of each treatment, we found that spraying 800-fold liquor of 15% Paclobutrazol wettable powder and 7,000-fold liquor of 5% Unlconazole (S3307D) on its leaves had significant dwarfing effect on it; 400-fold liquor of 50% chlormequat chloride (CCC) had not any. Cytological observation showed that after spraying Paclobutrazol and Unlconazole, the length of the epidermal cells of the stem became significantly shorter but not its width, its pilus epidermidis significantly shorter, the number of cells for each pilus epidermidis significantly less and the diameter of its sieve tube became significantly smaller. Paclobutrazol and Unlconazole inhibited the cell elongation and cell division, plant nutrient transportion and the growth of other parts of the plant, which were the main reasons of the Coleus blumei dwarfing. Spraying CCC on the leaves of Coleus blumei had no significant dwarfing effect, but had cytologic changes. The causes need further studying. The result indicated that Unlconazole had less aging effect on Coleus blumei, cytology traits were more stable, the surface of the plant looked smooth, which showed a higher ornamental value. Therefore, Unlconazole was a better dwarfing regulator of Coleus blumei.