The utility model relates to the technical field of plastic steel windows, and discloses a plastic steel window with a dustproof function, which comprises a window frame main body, a support rod is integrally formed in the middle of the window frame main body, plastic steel window main bodies are arranged on two sides of the window frame main body, and a fixing strip is arranged on one side, close to the support rod, of each plastic steel window main body. According to the technical scheme, due to the fact that the arc-shaped rubber plate is attached to the window frame body all the time, it is guaranteed that in the long-time push-pull process of the plastic steel window body, the attaching sealing effect of the arc-shaped rubber plate can be guaranteed due to abrasion, and the situation that outside dust enters a room is effectively avoided; and limiting rods can be turned over to be separated from arc-shaped rubber plates, then clamping strips on the arc-shaped rubber plates are pulled to be separated from clamping grooves, then the arc-shaped rubber plates are conveniently taken out and replaced, and the dustproof effect of the plastic steel window body is further improved.