The invention relates to a system and method for continuously sampling and measuring runoff and sediment in a soil and water conservation monitoring area. The system comprises a sampling subsystem, a measuring subsystem, a sample storage subsystem, a control subsystem, a power supply subsystem, a cleaning subsystem, a rainfall sensor and a plurality of sampling buckets, wherein the sampling subsystem, the measuring subsystem, the sample storage subsystem, the control subsystem, the power supply subsystem, the cleaning subsystem and the rainfall sensor are mounted in a box body with shutters on four surfaces; the plurality of sampling buckets surround an annular sampling track capable of intermittent rotation according to the water condition; the sampling buckets are connected with the annular sampling track through an automatic unlocking mechanism. The system and the method provided by the invention have the benefits that as a whole set of sampling buckets capable of being automatically recycled are arranged, the sampling buckets constantly sample the runoff generated in the area through the annular sampling track and record the sampling frequency; moreover, each sampling is accurately measured through the measuring subsystem, completely-unmanned automatic sampling and automatic measurement are realized, the field workload of scientific researchers is greatly reduced, and the labor and the use cost are saved.