The invention provides a coordinated control method and device for a synchronous phase modifier and LCC-HVDC (line-commutated-converter high voltage direct current). According to the coordinated control method and device, a fault judgment module is used to judge whether a fault occurs in an alternating current system, if the fault occurs in the alternating current system, turn-off angle deviationis calculated according to the turn-off angle of the LCC-HVDC; voltage deviation is determined according to the turn-off angle deviation, and the control input quantity of the synchronous phase modifier is calculated according to the voltage deviation; the excitation voltage of the synchronous phase modifier is determined according to the control input quantity of the synchronous phase modifier; and the coordinated control of the synchronous phase modifier and the LCC-HVDC is realized according to the excitation voltage of the synchronous phase modifier; and the capacity of the LCC-HVDC to resist commutation failures can be improved through the coordinated control of the synchronous phase modifier and LCC-HVDC. With the coordinated control method and device of the invention adopted, the capacity of the LCC-HVDC to resist commutation failures can be improved by means of the capability of the reactive power of the synchronous phase modifier to stabilize the voltage of a bus-bar, and theprobability of the commutation failure of the LCC HVDC can be decreased.