Let M n be a spacelike linear Weingarten submanifold in a de Sitter space S n+p p(1) with R = aH + b, where R and H are the normalized scalar curvature and the length of the mean curvature vector respectively. In this paper, we give intrinsic and extrinsic conditions for M n to be totally umbilical, respectively.Mathematics Subject Classification. 53C42, 53C40.