The invention discloses a generator set phase-in capacity mining method based on analog simulation. The method includes the steps that whether a generator set phase-in test has phase-in capacity mining space or not is judged; if the generator set phase-in test has phase-in capacity mining space, a station service system model is set up; a generator set in the station service system model is connected into a power grid simulation system, the generator set phase-in capacity in the low-load period state of a power grid is obtained through simulation by adopting operation data in the low-load period state of the power grid; after station service power source of a generator set is switched to a stand-by transformer power source, a phase-in test is carried out to obtain the own phase-in capacity of the generator set; the phase-in capacity of the generator set in the low-load period state of the power grid is compared with the own phase-in capacity of the generator set, and weak phase-in capacity is selected to serve as the phase-in capacity actually used in the low-load period state of the power grid. The required phase-in capacity of the generator set can be brought into full play, and the generator set phase-in capacity mining method can improve the safety level of power grid operation and has good application prospects.