A child tray assembly adapted for a child seat includes at least one support portion and a tray. The at least one support portion is slidably disposed on the child seat. The tray is detachably disposed on the at least one support portion. The tray includes a tray body and at least one sliding latch slidably disposed on the tray body. At least one assembling portion is formed on the tray body for insertion of at least one lower tube. The at least one sliding latch includes a first engaging portion and at least one second engaging portion. The first engaging portion is for engaging with the at least one support portion. The at least one second engaging portion is for engaging with the at least one lower tube inserted within the at least one assembling portion at a locking position.