The invention belongs to the technical field of photovoltaic power generation, and in particular to a grouping method for photovoltaic power stations on the basis of characteristic distances. The method comprises the following steps of: 1, numbering each power generation unit in the photovoltaic power stations, and reading the parameters of an inverter in each power generation unit; 2, selecting one power generation unit in the photovoltaic power stations, calculating the trace sensitivities of the parameters of the inverter in the power generation unit, and forming a column vector; 3, forming the parameters of the inverter in each power generation unit into a row vector; 4, calculating the characteristic distance between every two of all the power generation units; 5, setting a criterion value theta, if the characteristic distance between every two power generation units is less than theta, then dividing the power generation units meeting judgement conditions in the same group; or else, dividing the power generation units in different groups. The grouping method disclosed by the invention is capable of rapidly and conveniently grouping a large number of photovoltaic power generation units, clear in physical conception, and capable of providing a good basis for improving the accuracy of equivalent modelling.