Using the analytic calculation method from the multi-infeed interaction index and based on the reduced-order Jacobian matrix， the influence mechanism of control mode with respect to the converter bus voltage interaction in a multi-infeed AC-DC system is analyzed. It is shown that the power-voltage sensitivity of the inverter is one of the main factors influencing the voltage interaction strength. The equations of power-voltage sensitivity under different control modes are given. The impact of control modes on voltage interaction between inverters is analyzed by the test system.