Powering marine distributed nodes (e.g. monitoring buoys) has always been challenging under the harsh conditions in oceans. Triboelectric nanogenerator (TENG), on account of its robustness and cost, provide a novel solution to this problem. In this study, a stackable TENG (S-TENG) consisting of polytetrafluoroethylene pellets, an acrylic plates coated with aluminum film and a 3D-printed brace, has been proposed to harvest wave energy efficiently. Experiments show that each S-TENG unit produces a maximum peak power of 25.22mW while a power density of 34.65W/m3 is achieved. The output characteristic of multiple S-TENG units parallel connected is studied. It turns out that the output performance yields linear increase with the unit number without having to use rectifier bridge. This feature indicates that self-powered marine monitoring buoy is achievable by S-TENG integration.