The invention discloses a power transmission project prefabricated foundation installation and iron tower assembly coherent construction method which includes the following steps of re-measurement andpit dividing, construction plane design, ground tower assembly, foundation pit excavation, foundation backfill, process changing acceptance and overall tower erection. Through the technical scheme, aconstruction process of "foundation construction first, then tower assembly on the ground" in the prior art is adjusted to " tower assembly first, then foundation construction", the on-site development of a flow process mode of "personnel flow with machinery, continuous machinery operation and process close connection" is facilitated, the close connection of ten processes of "on-site re-measurement, pit dividing positioning, construction plane design, ground tower assembly, foundation pit excavation, prefabricated foundation transportation and installation, grounding installation, foundationbackfilling and compaction, process changing acceptance and overall tower erection" can be realized, the overall construction efficiency of the line foundation and the iron group assembly is improved,the construction period is shortened and controllable, the fully mechanized construction of the line engineering is realized, the economic benefits are significant, and the safety risks are reduced.