In order to investigate the aerodynamic and infrared characteristics of serpentine 2-D convergent-divergent exhaust system, three serpentine 2-D exhaust system with right behind full-shield convergent-divergent nozzle were designed. The effect of centre line offset-diameter ratios between throat and outlet, (S₈-S₉)/D=0.26-0.3, and width expansion ratios between throat and outlet, (W₉-W₈)/D=0.1-0.36, on aerodynamic and infrared characteristics was studied numerically. The results show that relative to the axisymmetric exhaust system, the infrared radiation intensity of three serpentine 2-D convergent-divergent exhaust systems decrease by 73.4% on average in the range of 0°-15° for tail direction, and decrease at least 60.3% in the 90° direction of side, upper, lower detection plane, the decrease of infrared radiation characteristics increases with the decrease of (S₈-S₉)/D, increases with the increase of (W₉-W₈)/D, and more sensitive to (S₈-S₉)/D. The thrust coefficient of three serpentine 2-D convergent-divergent exhaust systems increases with the decrease of (S₈-S₉)/D and (W₉-W₈)/D.