The invention provides a power system state estimation method with flexible DC control characteristics being considered. The method comprises the following steps: obtaining remote signaling and remote measurement data; carrying out topology analysis and forming a measurement equation and a reference jacobian matrix; judging whether current flexible DC control mode combination obtained through SCADA belongs to a feasible control mode set; carrying out correction on the jacobian matrix; solving an AC/DC system; estimating residual error through boundary nodes and judging reliability of the estimation result; correcting the jacobian matrix; transferring each control mode to one child thread; solving calculation tasks in each process in parallel and summarizing object function values; serving the calculation result corresponding to a control mode corresponding to the minimum object function value as the final result; and serving the control mode corresponding to the final result as the control mode of a current flexible DC control system. The system realizes dynamic monitoring of the flexible DC control mode and prevents bad influence on state estimation caused since the control mode changes, while set values in a regulation and control system fails to change in time.