A quick folding structure for a post unit of a tent frame includes upper, middle and lower posts, an upper connector, and a lower connector. The upper connector is disposed between the upper and middle posts and includes a first upper connecting portion and a second upper connecting portion. The lower connector is disposed between the middle and lower posts and includes a first lower connecting portion and a second lower connecting portion. A wire rope has a first end secured to the first upper connecting portion and a second end connected to a pin. A spring and the pin are disposed in a ladder-shaped trough of the first lower connecting portion. Two ends of the spring engage with the ladder-shaped trough and a first end of the pin, respectively. A second end of the pin faces an engaging notch of the second lower connecting portion.