The invention provides a wind power plant grid-connection point reactive power control method and device. The method is characterized by, to begin with, determining voltage deviation of a wind power plant grid-connection point; then, determining a reactive power distribution coefficient of a wind generation set; and finally, determining a reactive power reference value of the wind generation set.The voltage of the grid-connection point of the wind power plant is regulated and controlled by changing reactive power output of the wind generation set in the wind power plant and without additionally increasing a reactive power compensation device, so that automatic operation and management level of the wind power plant can be improved, and investment cost of the reactive power compensation device of the wind power plant is reduced; reactive power regulation amount of the wind power plant grid-connection point is calculated according to difference of selected control modes of the wind powerplant, thereby increasing flexibility of reactive power control of the wind power plant; and when the reactive power reference value of the wind generation set in the wind power plant is configured,equivalent reactance of each power generator set to the low-voltage side of the wind power plant booster station is considered, thereby improving regulation precision of the reactive power of the windpower plant and reducing regulation times.