Objective: This paper is to research the influence of covering plastic mulch on the yield and characteristics for Salvia miltiorrhiza

and the results will give a method to improve the cultivation and quality of the medicine plant. Method: The biological characteristic was investigated in the field. HPLC method was used to determine the liposoluble constituents (dihydrotanshinone

cryptotanshinone

tanshinoneⅠ

tanshinoneⅡA) and water-soluble constituents (salvianolic acid B

rosemarinic acid) of the difference cultivation mode. Result: The fresh and dry weight was increased by 18.20% and 48.62% under the cultivated condition by covering plastic mulch compared to the traditional cultivation. Meanwhile

the drying rate of the root cultivated by covering plastic mulch was increased by 23.08% compared to the condition without covering plastic mulch

while the dry rate of the up ground was decreased by 6.13%. The contents of liposoluble constituents and salvianolic acid B in the root cultivated by covering plastic mulch were increased 58.20% and 16.06%

respectively. Conclusion: The growth of S. miltiorrhiza could be improved by covering plastic mulch

meanwhile

the yield and the contents of constituents were increased significantly.