A remote backup system comprising: a first computer, including at least one control unit and at least one storage unit, wherein the storage unit executes at least one operating system program and at least one application program; and a cloud server, electronically connected to the first computer, wherein when the first computer is actuated to execute a shutdown procedure, the control unit commands the operating system program or the application program to record an executing status or an executed file and to generate a corresponding backup file, the control unit transmit the backup file to the cloud server, and the cloud server saves the backup file; wherein when the first computer is booted again and executes a start procedure, the control unit transmits a command signal to the cloud server, the cloud server receives the command signal and returns the backup file of the first computer to the control unit, and the control unit receives and loads the backup file to restore the operating system program or the application program to the system status before the shutdown procedure; and a second computer, electronically connected to the cloud server, including a control unit and a storage unit; wherein when the second computer is actuated to execute the start procedure, the control unit transmits a command signal to the cloud server, the cloud server receives the command signal and correspondingly returns the backup file of the first computer to the control unit of the second computer, and the control unit receives and loads the backup file to restore the operating system program or the application program to the system status of the first computer before the shutdown procedure; wherein, the control unit determines the versions of the operating system program and/or the application program and correspondingly generates information about the versions, and the information about the versions is combined into the backup file for verifying whether the backup file is suitable for the second computer when the second computer is loading the backup file, and the control unit commands shutdown of the operating system program or the application program. a first computer, including at least one control unit and at least one storage unit, wherein the storage unit executes at least one operating system program and at least one application program; and a cloud server, electronically connected to the first computer, wherein when the first computer is actuated to execute a shutdown procedure, the control unit commands the operating system program or the application program to record an executing status or an executed file and to generate a corresponding backup file, the control unit transmit the backup file to the cloud server, and the cloud server saves the backup file; wherein when the first computer is booted again and executes a start procedure, the control unit transmits a command signal to the cloud server, the cloud server receives the command signal and returns the backup file of the first computer to the control unit, and the control unit receives and loads the backup file to restore the operating system program or the application program to the system status before the shutdown procedure; and a second computer, electronically connected to the cloud server, including a control unit and a storage unit; wherein when the second computer is actuated to execute the start procedure, the control unit transmits a command signal to the cloud server, the cloud server receives the command signal and correspondingly returns the backup file of the first computer to the control unit of the second computer, and the control unit receives and loads the backup file to restore the operating system program or the application program to the system status of the first computer before the shutdown procedure; wherein, the control unit determines the versions of the operating system program and/or the application program and correspondingly generates information about the versions, and the information about the versions is combined into the backup file for verifying whether the backup file is suitable for the second computer when the second computer is loading the backup file, and the control unit commands shutdown of the operating system program or the application program.