The invention provides a starting method of a multi-end flexible direct-current power transmission system containing full-bridge modules. The method includes the following steps that: a direct-currentbus-bar circuit breaker is closed; series-connected alternating-current circuit breakers of starting resistor branch circuits of each phase of each single-end flexible direct-current power transmission system are closed, so that starting resistors of each phase of each single-end flexible direct-current power transmission system are enabled, and each single-end flexible direct-current power transmission system is made to enter an uncontrolled rectification charging state; the capacitors of all full-bridge modules on each bridge arm in which current flows from bottom to top in at least one single-end flexible direct-current power transmission system are cut off, and a cut-off state is maintained until the charging of all sub-modules is completed; and the alternating-current circuit breakers on the starting resistor branch circuits of each phase are disconnected, so that the starting resistors of each phase of each single-end flexible direct-current power transmission system are cut off, and after the voltage of the sub-modules of each single-end flexible direct-current power transmission system is stable, each single-end flexible direct-current power transmission system is unlocked. With the starting method of the invention adopted, the problem of severe voltage abrupt change occurs between a positive direct-current bus-bar and a negative direct-current bus-bar after the systems are unlocked can be solved.