A server rack assembly for supporting a receiving bracket accommodating a plurality of electronic components, includes a base, a pair of rails mounted on the base, and at least one pair of securing brackets. The base spacedly protrudes two pairs of opposite stands. At lease one first positioning hole is defined in each stand. Each rail spans between the respective stands and is mounted thereon. One of the securing brackets is securely mounted on a rear end of one of the rails, and the other securing bracket is slidably attached to a front end of the rail. Each securing bracket protrudes at least one positioning member for inserting in the at least one first positioning hole. A sliding member attached to each securing bracket elastically abuts against one corresponding stand for preventing the positioning member being disengaged from the positioning hole of the stand.