The invention provides a method and a device for evaluating energy storage unit power distribution of an energy storage power station. The method comprises: calculating power-energy state SOE relevancy of a battery pack string, according to the power-SOE relevancy, evaluating power distribution conditions of an energy storage unit on each battery pack string in an operation process; according to the power-SOE relevancy, calculating a power-SOE relevancy standard deviation coefficient of the battery pack string, according to the standard deviation coefficient, evaluating dispersion degree of the power-SOE relevancy of the battery pack string at each time in an operation process of the energy storage unit; and according to the standard deviation coefficient, calculating a standard deviation coefficient aggregate value of the power-SOE relevancy of the battery pack string, and according to the aggregate value, evaluating variation trend of battery pack string power distribution by the energy storage unit with run time. The method and the device solve technical problem in the prior art that power distribution of a battery pack string cannot be effectively evaluated, and a technical effect of effectively evaluating power distribution of the battery pack is achieved.