This paper presents a gaze estimation algorithm using integral projection of eye images with advantage of low additional hardware requirement and low computational power. The algorithm needs only a webcam under nature light source and captured eye images in a non-intrusive way. Before integral projection, we used binarization process to eliminate the non-related image information to gaze position. Projected on binary eye images with projection adjustment method to avoid eye tilt makes projection error and defined the accurate integral range of eye ROI images to achieve robust gaze estimation. We analyzed the projection diagram with skewness to describe the variation of different gaze position. In skewness calculation, the pixel coordinate of eye ROI images has been normalized to avoid head moved back and forth makes the size of ROI changed. In horizontal direction, the error angle of our algorithm is 2.29°, maximum error angle is 4.8° and the resolution we defined is 7.5. Because our algorithm is inaccurate in vertical, we could only estimate gaze direction, but to estimate precise angle. The computational power of our algorithm is low, the average execution time of each frame is only 0.01652 s, only 24% of opponent.