A computer-implemented method, non-transitory, computer-readable medium, and computer-implemented system are provided for data transmission in a trusted execution environment (TEE) system. The method executed by a first thread in multiple threads on a TEE side includes: obtaining first data; obtaining a TEE side thread lock; obtaining a write offset address and a read offset address respectively by reading a first address and a second address; determining whether a quantity of bytes of the first data to be transmitted is less than or equal to a quantity of writable bytes; if the quantity of bytes of the first data is less than or equal to the quantity of writable bytes, writing the first data into third addresses starting from the write offset address; updating the write offset address in the first address; and releasing the TEE side thread lock.