Abstract: This paper analyzes the characteristic of HFC upstream channel, proposes that using SCDMA can obtain stable transmission on the condition of very low SNR. S-CDMA has an ability to resist many kind of narrow-band interference and noises, but the multi-access interference induces the capacity and performance of the system. After analyzing several multiuser detectors, this paper uses decorrelating decision-feedback detector in HFC upstream channel S-CDMA system. It can cancel the interference of the stronger users and make advantages to the decision of the weaker users, thus can cancel the multiaccess interference and has better near-far resistance. Its complexity is linear in the number of users. The system need not accurate synchronization control, thus is simplified.