The invention provides a haze-preventing sliding window comprising a window frame. A fixed window sash and a sliding window sash are arranged in the window frame; a haze-preventing filter box connected with the window frame is arranged at the right end of the inner side of the window frame and internally provided with an air filter element; a sliding rail is arranged on the top of the window frame; a groove is formed in the bottom of the window frame and internally provided with a plurality of rollers capable of rotating freely; and magnetic strips are arranged on the right side of the slidingwindow and the window frame correspondingly, an inserting groove is formed in the contact position of the window frame and the right side of the sliding window sash, and the magnetic strips are arranged in the inserting groove. The multiple rollers are additionally arranged in the grooves formed in the bottom of the window frame, so that face-to-face contact between the sliding window sash and the window frame is converted into line-to-face contact between the sliding window sash and the rollers, friction force generated in sliding of the sliding window sash can be reduced, and the service life of the window is prolonged; and through arrangement of the haze-preventing filter box, air entering the indoor space can be filtered under the opening state of the sliding window sash, tiny dust and particles in the air can be blocked effectively, and health of the people is guaranteed.