[Objective] By testing the internal bacterial growth of SKWP mutants generated in Ralstonia solanacearum strain OE1-1, we evaluated the contribution of these SKWP effectors to bacterial fitness towards host plants. [Methods] The deletion mutant and complementation mutant of R. solanacearum OE1-1 were constructed. A competition assay in mixed infection was adopted to evaluate the contribution of the SKWP to bacterial fitness in tobacco (Nicotiana tabacum cv. Bright Yellow) and eggplant (Solanum melongena cv. Senryo-nigou). [Results] Eggplant was the appropriate host for competitive index (CI) assay of R. solanacearum strain OE1-1. All 6 SKWP mutants affected bacterial fitness in eggplant to some extent while SKWP4 appeared to be most important.[Conclusion] The SKWP effectors were important for bacterial proliferation in eggplant tissues according to the CI analysis, which paving a new way for further identification of the function on whole SKWP family.