This paper proposes a sensor based navigation method with fuzzy combiner for navigation of mobile robot in uncertain environments. The proposed navigator consists of two main behaviors: a reaching the middle of a collision-free space behavior, and goal-seeking behavior. The fuzzy combiner can fuse low-level behaviors so that the mobile robot can go for the goal position without colliding with obstacles. The fuzzy combiner is a soft switch that chooses more then one low-level action to be active with different degrees through fuzzy combination at each time step. The output of the navigation level is fed into a fuzzy tracking controller that takes into account the dynamics of the mobile robot. Computer simulation have been conducted to illustrate the performance of the proposed fuzzy combiner of behaviors by a series of experiments on the emulator of wheeled mobile robot Pioneer-2DX.