A method for upgrading a cloud desktop, comprising: building a base image of an operating system in advance (101, 401); wherein, an independent disk is allocated individually to a virtual machine corresponding to a cloud desktop, and the base image is configured for starting the operating system of the virtual machine, and the independent disk is configured for storing private data of a user and a record of a modification made by the user to a system disk, such that the virtual machine is able to acquire the private data of the user and the record of the modification to the system disk by mounting the independent disk during running; and upgrading the base image (103, 405), and synchronously updating the independent disk according to the upgraded base image (104, 406), the updated independent disk corresponding to the upgraded base image; wherein synchronously updating the independent disk according to the upgraded base image comprises: cloning the upgraded base image to generate two upgraded differential images, one of which is configured for starting the operating system of the virtual machine, and the other is configured for creating a guestfile; in response to starting the operating system of the virtual machine and the virtual machine being in a synchronous state, mounting a virtual disk file and the other differential image configured for creating a guestfile; acquiring a record of a modification to a file during upgrading the base image; and updating the guestfile and a registry of the virtual machine according to the record of the modification to the file. building a base image of an operating system in advance (101, 401); wherein, an independent disk is allocated individually to a virtual machine corresponding to a cloud desktop, and the base image is configured for starting the operating system of the virtual machine, and the independent disk is configured for storing private data of a user and a record of a modification made by the user to a system disk, such that the virtual machine is able to acquire the private data of the user and the record of the modification to the system disk by mounting the independent disk during running; and an independent disk is allocated individually to a virtual machine corresponding to a cloud desktop, and the base image is configured for starting the operating system of the virtual machine, and the independent disk is configured for storing private data of a user and a record of a modification made by the user to a system disk, such that the virtual machine is able to acquire the private data of the user and the record of the modification to the system disk by mounting the independent disk during running; and upgrading the base image (103, 405), and synchronously updating the independent disk according to the upgraded base image (104, 406), the updated independent disk corresponding to the upgraded base image; wherein synchronously updating the independent disk according to the upgraded base image comprises: cloning the upgraded base image to generate two upgraded differential images, one of which is configured for starting the operating system of the virtual machine, and the other is configured for creating a guestfile; in response to starting the operating system of the virtual machine and the virtual machine being in a synchronous state, mounting a virtual disk file and the other differential image configured for creating a guestfile; acquiring a record of a modification to a file during upgrading the base image; and updating the guestfile and a registry of the virtual machine according to the record of the modification to the file. cloning the upgraded base image to generate two upgraded differential images, one of which is configured for starting the operating system of the virtual machine, and the other is configured for creating a guestfile; in response to starting the operating system of the virtual machine and the virtual machine being in a synchronous state, mounting a virtual disk file and the other differential image configured for creating a guestfile; acquiring a record of a modification to a file during upgrading the base image; and updating the guestfile and a registry of the virtual machine according to the record of the modification to the file.