The present invention provides a foldable display support, wherein when a support arm is in a standing state, a limiting sheet is located in a limiting part of a screen support rack for blocking, so only the forward/backward tilted angle of a screen can be adjusted, thereby preventing being unstable and falling due to the gravity center being overly backward. When the support arm is folded to a horizontal state, the gravity center is lowered, and a protrusion of a first cam abuts a protrusion of a second cam, such that the second cam axially moves and pushes the limiting sheet to be released from the limiting part of the screen support rack, at this moment, the screen is enabled to be backwardly rotated and folded to a horizontal state for reducing the occupied space, thereby ensuring the folding process to be smooth and stable and preventing from falling.