A high resolution single circle absolute coding technique is proposed to improve angle measure resolution, reduce disk dimensions, and overcome the shortcoming of low speed in traditional image encoder. The single circle absolute coding method is proposed by analyzing the relationship between disk reticle and resolution, a decoding method is proposed by using collimation light source and linear array image sensors, and the high resolution disk and decoding circuit are designed based on the proposed method. In the experiment, the diameter of single circle disk is 38 mm, the digit is 10, and the decoding of 10 bits coding is achieved. The proposed method has faster response frequency than the traditional coding method with the array image detector.