Abstract: Studies the discrete-time Internet congestion control algorithm based on queue length, thus adjusting the congestion rate in accordance to the queue length connecting the nodes in Internet so as to determine the date transmission rate of source nodes. Taking the control algorithm with time delays as a complex and dynamic nonlinear feedback system and analyzing the congestion control algorithm for discrete-time systems, the criteria for locally asymptotic stability are given at the balance points in discrete-time network system under conditions that the time delays of communication loops are different. Simulation results show the validity and practicability of the criteria for asymptotic stability.