A method for upgrading a terminal system performed by a first terminal, the method comprising: a.) obtaining version information of a second terminal, wherein the version information of the second terminal comprises at least a device model and a version number of system software of the second terminal (step 201); b.) if the device model of the second terminal is compatible with a device model of the first terminal, determining according to the version number of the system software of the second terminal and a version number of system software of the first terminal, whether system upgrade is to be performed on the first terminal (step 202); c.) if the first terminal determines that system upgrade is to be performed, establishing a first transmission connection to the second terminal, and receiving on the first transmission connection system software data indicated by the version number of the system software of the second terminal (step 203); d.) if the first transmission connection is interrupted, recording interruption point location information of a data packet of the system software that is already received when the first transmission connection is interrupted (step 204); e.) obtaining a version number of system software of a third terminal whose device model is compatible with the device model of the first terminal (step 205); f.) if the version number of the system software of the third terminal is equal to the version number of the system software of the second terminal, obtaining from the third terminal according to the interruption point location information system software data after an interruption point location indicated by the interruption point location information (step 206); g.) if the version number of the system software of the third terminal is greater than the version number of the system software of the second terminal, deleting all obtained system software data before an interruption point location that is indicated by the interrruption point location information (step 207); h.) after step g.), obtaining from the third terminal system software data indicated by the version number of the system software of the third terminal, so that the first terminal completes system upgrade on the first terminal according to the system software data (step 208). a.) obtaining version information of a second terminal, wherein the version information of the second terminal comprises at least a device model and a version number of system software of the second terminal (step 201); b.) if the device model of the second terminal is compatible with a device model of the first terminal, determining according to the version number of the system software of the second terminal and a version number of system software of the first terminal, whether system upgrade is to be performed on the first terminal (step 202); c.) if the first terminal determines that system upgrade is to be performed, establishing a first transmission connection to the second terminal, and receiving on the first transmission connection system software data indicated by the version number of the system software of the second terminal (step 203); d.) if the first transmission connection is interrupted, recording interruption point location information of a data packet of the system software that is already received when the first transmission connection is interrupted (step 204); e.) obtaining a version number of system software of a third terminal whose device model is compatible with the device model of the first terminal (step 205); f.) if the version number of the system software of the third terminal is equal to the version number of the system software of the second terminal, obtaining from the third terminal according to the interruption point location information system software data after an interruption point location indicated by the interruption point location information (step 206); g.) if the version number of the system software of the third terminal is greater than the version number of the system software of the second terminal, deleting all obtained system software data before an interruption point location that is indicated by the interrruption point location information (step 207); h.) after step g.), obtaining from the third terminal system software data indicated by the version number of the system software of the third terminal, so that the first terminal completes system upgrade on the first terminal according to the system software data (step 208).