The present invention provide cryo-conservation when Shen Dian does not occur and be able to maintain continuous single-phase have low-temperature stability water soluble herbicide constituent. The water soluble herbicide constituent of present invention offer, characteristic system include following (a) ~ (d): (a) water soluble herbicide composition (b) polyoxyethylene alkyl ether sulfate salt (c) organic solvent And (d) polyoxyethylene alkyl ether.