This paper has observed linewidth narrowing of dark states in rubidium cell by using the Hanle configuration.The reduction of the coherent resonance width under the transition of 87Rb Fg = 1 → Fe = 0 is observed and the qualitative explanation about its mechanism is presented. Multiple subnatural width dips are obtained with a linearly polarized laser beam for the transitions of 87Rb Fg = 1 → Fe = 0, 1, 2. The feature of negative and positive slope,namely dispersionlike feature, is observed in the transmitted light.