The invention discloses a dynamic reactive planning site-selection analysis method and system considering transient voltage stability. The dynamic reactive planning site-selection analysis method comprises the steps of obtaining related data of a power grid firstly; then performing simulation analysis on the transient voltage stability of the power grid, analyzing the power grid faults to determine a transient voltage instability fault set, and dividing the transient voltage instability fault set into multiple transient voltage stable weak regions; next, calculating the dynamic reactive compensation sensitivity under each fault state, and determining the number and locations of the to-be-compensated points of one of the power grid fault weak region through a panning site-location combinational analysis method; and finally, outputting the position scheme of the dynamic reactive planning site-selection to-be-selected points of all the transient voltage stable weak regions. Compared with the prior art, the dynamic reactive planning site-selection analysis method and system are suitable for dynamic reactive planning site-selection in the alternating current/direct current hybrid power grid, have the advantages of high efficiency, simplicity, tight combination with engineering and the like; and in addition, the redundancy of the dynamic reactive planning site-selection to-be-selected compensation points can be effectively prevented.