Abstract: The effect of plant growth retardants on seeds germination, seedling growth and photosynthetic characteristicswas tested by soaking M usella lasiocarpa seeds with p lant growth retardants ( PP333 , S3307 , CCC) for 24 hours.Results indicated that 10—40 mg·L-1 PP333 , 2—8 mg·L-1 S3307 soaking can delay the germination, decreasebiomass accumulation, reduce p lant height, furthermore increase chlorophyll content and enhance photosyntheticrate. The dwarf effect of 40 mg·L-1 PP333 was the most notable, the p lant height clearly descended by 51. 8%compared with the contrast; CCC soaking can also delay the germination, enhance photosynthetic rate but increasebiomass accumulation in certain degree. 5 000—7 000 mg·L-1 CCC soaking significantly delayed the germination,reduce p lant height. The dwarf effect of 7 000—10 000 mg·L-1 CCC soaking was not obvious, but significantlyincreased the chlorophyll content. Comparatively speaking, the dwarf effect of PP333 and S3307 on M usella lasiocarpawere better than that of CCC. Compared with PP333 , the dosage consump tion of S3307 was much smaller when thesame control levelwas obtained. S3307 wasmore suitable forM usella lasiocarpa seed soaking from the perspectives ofdwarf effect, photosynthesis and economy.