A damped linear accelerating structure using a choke-mode cavity has been proposed for future e + e − linear colliders as the main accelerating structure . A constant-gradient C-band accelerating structure was designed using the MAFIA code [2,3]. The operation mode and frequency are 3π 4 and 5.712 GHz. The Q -value of the accelerating structure is about 84% of conventional accelerating structures, and the shunt impedance is about 75% of conventional accelerating structures. The total attenuation (τ) of the accelerating structure with a choke cavity shows a 35% increase compared to that of a conventional disk-loaded accelerating structure. This paper presents the preliminary simulation results.