Embodiments of the present invention disclose a signal sending method and apparatus and a signal receiving method and apparatus. The signal sending method includes: generating, by a network device, a first signal, where the first signal includes at least one sequence pair, each of the at least one sequence pair includes two sequences, and an element value of one sequence of the two sequences is a value obtained by calculating, according to a first calculation rule, an element value of the other sequence of the two sequences and an element value of a first sequence corresponding to the other sequence, where each sequence in the at least one sequence pair and the first sequence are complex sequences with lengths greater than 1; and sending, by the network device, the first signal to a terminal device.