The technology of this application relates to a transaction security processing method and apparatus, and a terminal device. The method includes receiving, in a rich execution environment (REE), a screen jump instruction triggered by a user in a first screen, where the screen jump instruction is used for jumping to a second screen, and the second screen can be displayed in a trusted execution environment (TEE), and entering the TEE and loading a trusted application (TA) in the TEE. The method further includes obtaining a first audio file from storage space on an REE side and playing the first audio file by using the TA, where the first audio file is used to represent that the terminal device is currently running in a trusted environment, and displaying the second screen generated by using the TA.