In this paper, we investigate the existence of positive solutions for fourth order singular p-Laplacian differential equations with integral boundary conditions and non-monotonic function terms. Firstly, we establish a comparison theorem, then we define a partial ordering in E 0 and construct lower and upper solutions to give a necessary and sufficient condition for the existence of C 2 [0, 1] as well as pseudo-C 3 [0, 1] positive solutions. Our nonlinearity f (t, x, y) may be singular at x = 0, y = 0, t = 0 and t = 1. Finally, we give some the dual results for the other cases of fourth order singular integral boundary value problems and an example to demonstrate the corresponding main results.