Dismountable safety anti-theft grid

The utility model relates to a dismountable safety anti-theft grid, which comprises an upper outer frame, a lower outer frame, vertical beams and cross beams. The cross beams are positioned between the neighbouring vertical beams, the upper end of the vertical beam is positioned in the upper outer frame, the lower end of the vertical beam is positioned in the lower outer frame, and a movable bracket holding against the lower end of the cross beam is arranged in the lower outer frame. The utility model increases the safety of the anti-theft grid, and the glass outside the window can be easily cleaned. In addition, with the changed process technique, the color of the whole structure is diversified in order to match the colors of the outer wall, the window structure and the glass. The utility model eliminates all the welding points, increasing the intensity and rigidity of the whole structure, and is convenient to be produced and installed, realizing the standardized production. Moreover, the requirement for the precision of the window size is decreased, and the structure can be adjusted in a large range.