Abstract: On the basis of the traditional Littman external cavity diode laser, a novel optical method for wavelength tuning is proposed. A′refractive optical lever′system which consists of a rotating optical wedge prism is employed to reduce the requirement of the rotation mechanism for tuning and improve the accuracy of wavelength selection. By optimizing the vertex angle of the wedge prism and the incident angle of the light ray, the requirement of the rotation mechanism can be reduced by one or two orders of magnitude, and the wavelength selection accuracy can be improved as well. The characteristics of external cavity diode lasers are improved and its sensitivity to the vibration is reduced.