Abstract: For understanding whether pleuromutilin have toxic effects on the plants, the effect of pleuromutilin with different concentration (0, 0.00128, 0.0032, 0.0064, 0.016, 0.032, 0.08, 0.16 mg/mL) in media on potato seedlings’ of ‘Kexin 1’ cultivar were studied. The results show that when the concentration is greater than 0.016 mg/mL, the pleuromutilin have significant inhibition effect on the growth of potato seedling. With the increase of pleuromutilin concentration, the number of leaves, plant height, stem diameter, root length, and the dry weight of leaves, roots, and stem significantly decrease. Under the concentration of 0.08-0.16 mg/mL, potato plant become dwarf, mortality increases and has little or even no roots. The regression analysis shows that all the determined indexes decline with the concentration of pleuromutilin increase by a form of negative power function and the absolute value of power index are in the following order: dry weight of root> root length> dry weight of leaf> plant height> dry weight of leaf> number of leaf> stem diameter. Those suggest that pleuromutilin could have inhibition (toxic) effect on the growth of potato, and have the most suppression effect on root and the lowest suppression effect on leaf which could be resulted of direct contact of the root to pleuromutilin.