Let f be a smooth strictly convex solution ofdefined on a domain Ω C R^n, where ai, bi and c are constants. Then the graph Mvf of △f is a spacelike translating soliton for mean curvature flow in pseudo-Euclidean space with the translating vector（al, a2, . ., an; bz, b2, , bn）. In this paper, we will use alCfine technique to show a Berustein Theorem： if the graph Mvf is complete, then f（x） must be a quadratic polynomial and Mvf is an ailine n-plane.
： Let Lτ be the r-th affiue mean curvature of a hyperovaloid ia A^n＋1, in this paper,we prove that if Lτ≠0 and for some fixed1〈i1〈…〈iτ〈n,i=1∑τLij=Ceverywhereon M, then M must be an ellipsoid, where C is a constant.
