A thermally maintainable built-in storage tray structure can include a case main frame body; a storage unit tray is positioned within the case main frame body, and wherein the storage united is configured to be positioned at a front end of a server together with a mainboard and a PCI_E and the storage unit tray is moveably connected to the case main frame body and is capable of be pulling out of the case main frame body; a middle flip rack provided at a middle part and a rear flip rack provided at a rear part of the storage unit tray, the middle flip rack and the rear flip rack are hinged to the storage unit tray.