In the current work, the effect of Coriolis force is considered in a rotating rectangular rib-roughened channel. Time-resolved PIV (Particle Image Velocimetry) was used to measure the flow field. The Reynolds number is fixed at 10000, and the rotation numbers range from 0 to 0.52. The ribs obstruct the channel by 10%. The mean velocity fields and Reynolds shear stress fields are obtained. Due to the effect of Coriolis force, the flow fields are different between leading and trailing side. Furthermore, the vortex and the reattachment are also investigated. Based on the results, it can be inferred that Coriolis force plays a significant effect on the vortices. Coriolis force enlarges the vortex near the leading side, but suppresses the vortex near the trailing side. An interesting phenomenon has been found. Because of the Coriolis force pointing to the trailing side, the main stream is supposed to be pushed to the trailing side. But the results show that a velocity deficit appears near the trailing side. This phenomenon indicates that the Coriolis force is not the only force affecting the flow, but the secondary flow is also an important factor that cannot be ignored in a rotating ribbed channel.