The invention discloses a slope runoff and water chemical index comprehensive determination method. The method comprises the following steps: I, establishing a slope runoff and water chemical index comprehensive determination apparatus comprising a water pipe, a circular ring, a cylindrical or hemispherical shell, a skip-bucket rain gauge, a disc, a metal net, a cubic shell, a funnel, a 90-degree elbow, a horizontal PVC pipe, a tee joint, an inverted U-shaped pipe, a movable choke plug, a variable-diameter pipe head, a water collection bottle, a disc base and inner threads; II, introducing slope runoff into the skip-bucket rain gauge by virtue of the water pipe, after the rain gauge is fully filled with the water, enabling the rain gauge to roll automatically, enabling waste water to flow through the metal net, the funnel, the 90-degree elbow, the PVC pipe, the tee joint and the inverted U-shaped pipe to enter the water collection bottle so as to be used for the subsequent water quality determination and analysis, opening the movable choke plug at the tee joint, directly inserting an electric conductivity meter, and measuring the water temperature and the electric conductivity in real time. According to the method, the collection of the slope runoff and the water sample determination are integrated, the measurement system is comprehensive, and the collection and measurement accuracy can be improved.