Corrugated metal with period grooves supports spoof surface plasmons polariton (SSPP) wave in microwave and terahertz ranges. In this letter, a four-way SSPP splitter/combiner with oval-ring periodic structures is presented by using a single connection junction. Up to the authors' best knowledge, a four-way SSPP splitter/combiner is never reported in the literature. In order to verify the performance of the mentioned SSPP splitter/combiner, we have manufactured and tested the presented SSPP splitter/combiner. The simulation and measurement results demonstrate that the designed conversion between a single coplanar waveguide junction and four SSPP waveguides is high efficiency. The SSPP splitter equally separates the electromagnetic wave into four paths. Hence, the proposed four-way splitter is expected to develop the SSPP active and passive components and relative integrated circuits.