The invention discloses a method for improving resistance, yield and quality of field cultivated radix notoginseng by using polyethylene glycol (PEG) 6000, an osmotic adjustment substance that can simulate drought stress and is safe and non-toxic. According to the method, PEG 6000 aqueous solution is sprayed on blades of the radix notoginseng to form a moderate drought stress on radix notoginsengplants by means of strong moisture absorption capacity of the PEG 6000, so that the resistance of the radix notoginseng can be improved, the underground part growth of the radix notoginseng is promoted, and the yield of radix notoginseng medicinal materials and the content of total saponins are improved. The method is based on the core theory of the environment-induced regulation of biosynthesis of higher plant secondary products, a reagent used is common, cheap and easy to obtain, the processing is simple, the cost is low, the yield and quality of the radix notoginseng medicinal materials canbe improved conveniently and effectively, and the method is of positive significance for promoting benign development of the radix notoginseng industry and is suitable for being widely used as one ofthe routine measures for field management in radix notoginseng cultivation.