Embodiments of this application provide a data sending method, a data receiving method, a transmit-end device, and a receive-end device. The data sending method provided in the embodiments of this application may include: performing scrambling code initialization to generate a scrambling code; scrambling a data block based on the scrambling code; repeatedly sending the scrambled data block; performing scrambling code initialization to generate a new scrambling code when an interval after previous scrambling code initialization of the data block is greater than or equal to a preset scrambling code initialization parameter threshold; scrambling the data block again based on the generated new scrambling code; and repeatedly sending the data block scrambled again. The embodiments of this application can improve efficiency of data transmission between a transmit-end device and a receive-end device.