A secure data transmission apparatus, comprising a dedicated communication signal processor and an application processor, characterised in that: the dedicated communication signal processor is configured to send a first security interrupt to the application processor; the application processor is configured to: execute rich execution environment REE software, wherein the REE software comprises a client application CA that runs in REE; execute trusted execution environment TEE software under a trigger of the first security interrupt, wherein the TEE software comprises a trusted application TA that runs in TEE; and under driving of the TA, obtain first information from a shared memory of the dedicated communication signal processor and the application processor based on the first security interrupt, wherein the first information is information that the dedicated communication signal processor needs to transfer to the application processor, and security of the TEE software is higher than that of the REE software; the dedicated communication signal processor is further configured to receive a second security interrupt sent by the application processor, and obtain second information from the shared memory based on the second security interrupt, wherein the second information is information that the application processor needs to transfer to the dedicated communication signal processor; and the application processor is further configured to send the second security interrupt to the dedicated communication signal processor under the driving of the TA, wherein the second information is configuration information of a parameter specific to the dedicated communication signal processor, and a priority of the configuration information that the application processor transfers to the dedicated communication signal processor under the driving of the TA is higher than a priority of configuration information that the application processor transfers to the dedicated communication signal processor under driving of the CA. the dedicated communication signal processor is configured to send a first security interrupt to the application processor; the application processor is configured to: execute rich execution environment REE software, wherein the REE software comprises a client application CA that runs in REE; execute trusted execution environment TEE software under a trigger of the first security interrupt, wherein the TEE software comprises a trusted application TA that runs in TEE; and under driving of the TA, obtain first information from a shared memory of the dedicated communication signal processor and the application processor based on the first security interrupt, wherein the first information is information that the dedicated communication signal processor needs to transfer to the application processor, and security of the TEE software is higher than that of the REE software; the dedicated communication signal processor is further configured to receive a second security interrupt sent by the application processor, and obtain second information from the shared memory based on the second security interrupt, wherein the second information is information that the application processor needs to transfer to the dedicated communication signal processor; and the application processor is further configured to send the second security interrupt to the dedicated communication signal processor under the driving of the TA, wherein the second information is configuration information of a parameter specific to the dedicated communication signal processor, and a priority of the configuration information that the application processor transfers to the dedicated communication signal processor under the driving of the TA is higher than a priority of configuration information that the application processor transfers to the dedicated communication signal processor under driving of the CA.