The utility model provides a transformer substation's secondary equipment room cable laying device, including support piece, back timber, cable ladder, anti electrostatic floor and terrace, support piece includes that base, branch and 2 blocks of layer boards constitute integratively, support piece is fixed on the terrace of transformer substation by its base, support piece is to a plurality of rows of parallel arrangement around on the terrace, and support piece sets up a plurality of at every row of even interval, and per 2 rows of support piece are a set of, set up relatively with two rows of a set of support piece's layer board, the back timber is in the fixed setting respectively of every row of support piece's upper end, cable ladder sets up 2 respectively between per 2 rows a set of support piece, anti electrostatic floor lays on the up end of back timber. The utility model discloses simple structure, cost are lower, can ensure safely and easily overhaul and the dilatation in construction simple to operate and the use.