The embodiment of the invention relates to the technical field of software, and discloses a cloud desktop upgrading method and device, a cloud server and a storage medium. In the embodiment of the invention, the cloud desktop upgrading method comprises the following steps: manufacturing a basic mirror image of an operating system in advance, wherein an independent disk is independently allocated to a virtual machine corresponding to a cloud desktop, the basic mirror image is usd for starting the operating system of the virtual machine, the independent disk is used for storing private data of auser and change records of the system disk by the user, so that the virtual machine obtains the private data of the user and the change records of the system disk by mounting the independent disk during running; upgrading the basic mirror image, synchronously updating the independent disk according to the upgraded basic mirror image, wherein the updated independent disk comprises the upgraded basic mirror image. By adopting the embodiment of the invention, the unified upgrading and maintenance of the cloud desktop are realized, the system resource consumption is reduced, and the user experience is improved.