The invention relates to a two-domain interconnection system load frequency control method based on frequency division control and aims to control load frequency of a two-domain interconnection electric power system comprising a wind power generation set, a traditional thermal power generation set and a cell energy storage system. The method comprises steps that 1), the two-domain interconnection electric power system is constructed according to mathematics models of the traditional thermal power generation set, the wind power generation set and the cell energy storage system; 2), an interference observer for the cell energy storage system and a sliding mode load frequency controller for the traditional thermal power generation set are respectively designed; and 3), an ACE frequency division control method based on filtering is employed, and control on the load frequency of the two-domain interconnection electric power system is carried out. Compared with the prior art, the method is advantaged in that frequency division control is realized, fast response is realized, and precision is improved.