Abstract: The Light Ⅱ-B was built at the side of the Marx tank of Light Ⅱ-A for X-pinch testing. It is composed of an old Marx generator, a new pulse forming line (PFL), a new gas-filled switch, a new pulse transmission line (PTL) and a new cavity load. The Light Ⅱ-B not only keeps its original ability of KrF, but also can be used for X-pinch research. The pulse forming line was a water-filled coaxial transmission line with the output impendence of 6 Ω, which was filled with deionized water using a new vacuum pressure technique. The Rogowski coil was adopted to measure the current crossing the load. The preliminary experiment was done with cavity load. The results show that for the 269 kA/50 ns pulse power generator (Light Ⅱ-B) for X-pinch experiments, the current rise time is no more than 30 ns when the Marx generator charge is 1.4 MV, and about 80% of the current can be used by the load.