The embodiment of the invention discloses a digitalized transformation method for a transformer substation. The digitalized transformation method comprises an original bus protection device upgrade step, a total-interval sub-machine analog quantity and IO quantity conversion step, a total-interval sub-machine data transmission step, a step of converting GOOSE receiving quantity into IO quantity, a duty-cycling control interval transformation step and a total-interval sub-machine exit step; after an entire station SCD file is configured, the SCD file is subjected to privatization configuration and then is unloaded into a total-interval sub-machine; associated configuration information of all untransformed intervals required for a digitalized bus difference is modified to be completely transmitted by the total-interval sub-machine; meanwhile, a virtual terminal of requiring conventional tripping operation in digitalized bus difference GOOSE tripping information is associated into the total-interval sub-machine for opening; and a fiber connecting line only needs to be modified to be connected to an intelligent terminal and a merging unit (MU) corresponding to the terminal by the total-interval sub-machine when each interval is transformed each time, so that seamless switching of the total-interval sub-machine is achieved; and the digitalized transformation method has the technical effects of small boundedness, high operability, safety, reliability, simplicity in construction and high transformation efficiency.