The invention discloses a method for determining a mine construction parameter of a water-soluble viscosity reducer. The method comprises the following steps of S1, analyzing and evaluating influenceof a viscosity reducing mode of the water-soluble viscosity reducer at an indoor space, and determining an injection mode of the viscosity reducer S2, analyzing the influence of oil reservoir water content to the viscosity reducing effect of the water-soluble viscosity reducer, and influence of viscosity reducer adding amount to a viscosity reducing effect of crude oil, determining the applicationconcentration of the viscosity reducer and calculating the application amount of the viscosity reducer; S3, analyzing the emulsification characteristic of the viscosity reducer and emulsion stabilitythereof, performing comparison according to the balance time of an injection pressure, and determining a soak time; and S4, according to the construction parameters which are determined in the stepsS1-S3, thereby forming the construction parameter of the water-soluble viscosity reducer. The method aims at the water-soluble viscosity reducer in a chemical viscosity reducing technique and is established according to the technical facility of the construction process. A theory is combined with reality, thereby guiding the construction application of the chemical viscosity reducing technique ofthe mine.