This paper proposes a visual perception system to detect and track the lanes and line-markings by using multiple RGB-D cameras. The RGB-D cameras can provide depth and color information to collect the data of 3D surrounding view. The 3D surrounding information can be projected to 2D images with various viewing angles from which the drivable space is easily extracted. The morphology algorithm is then used to detect the line-markings on the drivable space. These lines can be continuously tracked during the mobile robot moving.