To study the influence of slenderness on the compressive bearing capacity of autoclaved fly ash perforated brick masonry long columns and provide experimental evidences for making corresponding technical code, compression tests were conducted on 9 autoclaved fly ash perforated brick masonrys long columns of different slenderness. The damage patterns and compression performance are analyzed. The experimental results indicate that compressive capacity decreases proportionally as slenderness increases and the proposed formula of axial compressive bearing capacity for autoclaved fly ash perforated brick masonry columns is given. The nonlinear FEA program ANSYS is also adopted to simulate the behaviors of masonry columns. By comparing results find that the simulated results agree well with the test ones, the rationality and applicability of the model are verified.