This paper studies experimentally and numerically flow uniformity in various interconnects and its influence to temperature distributions and cell performance of a planar solid oxide fuel cell (SOFC). A transparent hydraulic platform is first established to evaluate the degree of flow uniformity in many different modules of interconnects using the same rib- channels for both the cathode and the anode or using Ni-mesh without rib-channels only for the anode side. This novel setup allows direct imaging and measurements of flow uniformity in both rib-channels and Ni-mesh, so that these experimental data can be used to validate numerical flow data. A three- dimensional numerical model using CFD-RC package with sub- models is then used to simulate various transport phenomena and electrochemical reactions of a single cell with the consideration of different degrees of flow uniformity in interconnects. It is found that previous modules using either single-inlet/single-outlet or double-inlets/single-outlet designs cannot provide uniform velocity distributions in these rib-channels, which can result in serious non-uniform temperature gradients in the cell. We propose a new design, using small guide vanes equally-spaced around the feeder of the double-inlet module on the cathode side and using Ni-mesh on the anode side, which features a highest degree of flow uniformity and least non-uniform temperature gradients in the cell among all different modules studied.