An auxiliary terminal-control apparatus, wherein the auxiliary terminal-control apparatus comprises a back plate sticker, a control key embedded into the back plate sticker, a communications module, and a control module, wherein the control module is configured to recognize a target operation on the control key, and generate, based on the target operation, a corresponding target operation instruction, wherein the control key comprises a roll ball and operations on the roll ball comprise a roll operation and a press operation; and the communications module is configured to establish a communication connection to a terminal device to send the target operation instruction to the terminal device, wherein the target operation instruction is used to operate an application program or trigger a service on the terminal device; wherein the auxiliary terminal-control apparatus further comprises: a storage module, configured to store configuration information, wherein the configuration information comprises a correspondence between an operation on the control key and a generated operation instruction; wherein the control module is specifically configured to determine, based on the target operation, the target operation instruction from the configuration information; characterized in that: the configuration information comprises: generating a slide operation instruction for a touchscreen of the terminal device based on a roll operation on the roll ball; and further wherein the configuration information further comprises: generating a selection operation instruction based on a press operation on the roll ball, so as to select a location at which the slide operation currently stops. the control module is configured to recognize a target operation on the control key, and generate, based on the target operation, a corresponding target operation instruction, wherein the control key comprises a roll ball and operations on the roll ball comprise a roll operation and a press operation; and the communications module is configured to establish a communication connection to a terminal device to send the target operation instruction to the terminal device, wherein the target operation instruction is used to operate an application program or trigger a service on the terminal device; wherein the auxiliary terminal-control apparatus further comprises: a storage module, configured to store configuration information, wherein the configuration information comprises a correspondence between an operation on the control key and a generated operation instruction; wherein the control module is specifically configured to determine, based on the target operation, the target operation instruction from the configuration information; characterized in that: the configuration information comprises: generating a slide operation instruction for a touchscreen of the terminal device based on a roll operation on the roll ball; and further wherein the configuration information further comprises: generating a selection operation instruction based on a press operation on the roll ball, so as to select a location at which the slide operation currently stops. a storage module, configured to store configuration information, wherein the configuration information comprises a correspondence between an operation on the control key and a generated operation instruction; wherein the control module is specifically configured to determine, based on the target operation, the target operation instruction from the configuration information; characterized in that: the configuration information comprises: generating a slide operation instruction for a touchscreen of the terminal device based on a roll operation on the roll ball; and further wherein the configuration information further comprises: generating a selection operation instruction based on a press operation on the roll ball, so as to select a location at which the slide operation currently stops.