This paper presents a strategy that efficiently allocates the limited resource and still maintains the coding performance for the spatial scalability of H.264/SVC. An integrated computation-scalable algorithm is proposed based on mode decision and adaptive search range. The RD-cost of the base layer is used as the priority to decide the mode in the enhancement layer, and the motion vector difference in the base layer is employed to determine the search range as well. Through the proposed approach, computation complexity of the enhancement layer could be reduced efficiently and well allocated. Experimental results demonstrate that the saving time reaches up to 82% and the computation scalability is realized.