A cowl cross member assembly for a vehicle for improving convenience in mounting a steering module and avoiding interference with an audio system in a vehicle, may include a main cowl crossbar disposed at a driver's seat in a width direction of the vehicle, a sub-cowl crossbar disposed at a passenger's seat in the width direction of the vehicle, a connection unit disposed between one end of the main cowl crossbar and one end of the sub-cowl crossbar and connecting the main cowl crossbar with the sub-cowl crossbar, a cowl bracket coupled to the main cowl crossbar at one side and coupled to a vehicle body at another side, a steering bracket coupled to a bottom of the cowl bracket and coupled to the steering module, and a steering mounting unit coupled to the main cowl crossbar at one side and coupled to the steering module at another side.