This paper develops a blind adaptive interference suppression algorithm for simultaneously suppressing multiple-access interference (MAI) and narrow-band interference (NBI) in direct sequence code division multiple-access (DS-CDMA) systems.This method is based on RLS with a self-tuning regulator for the forgetting factor(SR-RLS).When the system becomes stationary

the forgetting factor approaches to unit for a small steady-state error

while the system is dynamical

then the forgetting factor decreases to make the novel algorithm possess the ability to track dynamical parameters.Compared with other RLS algorithms

it has smaller steady-state error and better ability of tracking dynamical parameters.The convergence of the algorithm is theoretically analyzed.Lastly through simulation the performances of the algorithm under the stationary and dynamical environments are investigated respectively.