This paper presents a kind of high efficiency spreading spectrum modulation scheme using double orthogonal complex sequences (DoCS). In this scheme, input data bit-stream is split into many groups with length M. Each group is then mapped into a word of width M and then utilized to select one sequence from 2M-2 DoCS sequences each with length L. After that, the selected sequence is modulated on carrier in QPSK(quadrature phase shift keying) mode. In addition, a novel method named forward phase correction (FPC) is put forward for carrier recovery.