Embodiments of the present invention provide a transmission status determining method, where the method includes: receiving, by a receive end device in a first time period, a first symbol sequence sent by a transmit end device; determining a first modulation parameter set according to the first symbol sequence; and determining, according to preset first mapping relationship information, a first transmission status corresponding to the first modulation parameter set as a transmission status of the transmit end device in a second time period, where the first mapping relationship information is used to indicate a one-to-one mapping relationship between N transmission statuses and N modulation parameter sets, the first modulation parameter set belongs to the N modulation parameter sets, and the second time period is later than the first time period.