The invention provides an electric automobile charging device and method. The electric automobile charging device comprises a frequency detecting module, a response control module and an ultra-short-term prediction module, wherein the input end of the frequency detecting module is electrically connected with an access grid, the output end of the frequency detecting module is connected with the response control module through the ultra-short-term prediction module, the response control module is electrically connected with an electric automobile battery pack, the variation tendency of a power grid in the future is analyzed through the ultra-short-term prediction module, it is determined that a detection result is effective when the difference of a predicted frequency deviation and a detected frequency deviation is in a certain threshold value, the reasonable reliability of the power grid frequency variation detection result is improved, and frequency response reliability is improved.