Let A and B be standard operator algebras on Banach spaces X and Y, respectively. Let ϕ, : A →,B be a bijective map. In this paper, we show that ϕ,is completely Preserving quadratic operator in both directions if and only if ϕ,is 2-quadratic Preserving operator in both directions and if and only if ϕ,is either an isomorphism or (in the complex case) a conjugate isomorphism.