The invention discloses a transmission and distribution network coordinated planning method based on distribution network equivalents. The method comprises the steps that a distribution network equivalent model based on a universal stop table is established; on the basis of each established distribution network equivalent model, probability load flow calculation is carried out on the transmission network side through an analytic method or a simulation method; and finally, required power grid planning evaluation indicators are acquired to evaluate a power grid planning scheme. According to the method, the distribution network equivalent form is adopted to take the influence of the distribution network side on a transmission network into consideration when power grid planning is carried out, and transmission and distribution network coordinated planning is realized.