It is well known that increasing functions do not preserve operator order in general; nor do decreasing functions reverse operator order. However, operator monotone increasing or operator monotone decreasing do. In this article, we employ a convex approach to discuss operator order preserving or conversing. As an easy consequence of more general results, we find non-negative constants γ and ψ such that A ≤ B impliesfor the self adjoint operators A, B on a Hilbert space H with identity operator 1 H and for the convex function f whose domain contains the spectra of both A and B.The connection of these results to the existing literature will be discussed and the significance will be emphasized by some examples.