The invention relates to the technical field of electric power, in particular to a power system vector diagram drawing device and method. The device comprises a vector acquisition module, a calculation processing module, a graph drawing module, a sequence component calculation module, a power calculation module and a vector operation module. The method is novel in design, greatly improves the drawing speed and accuracy of the vector diagram, avoids human errors, improves the working efficiency, achieves intelligent drawing, helps metering, relay protection and other professions to quickly drawthe complex vector diagram, and achieves calculation and drawing of positive-sequence, negative-sequence and zero-sequence components. When asymmetric faults such as short circuit and disconnection exist in the system, negative-sequence and zero-sequence components are rapidly calculated, a basis is provided for power system fault judgment, the fault judgment and positioning speed is increased, the investment is low, and large-scale popularization can be achieved.