A reference signal sending method, comprising: generating, by a network device, reference signals that are of N antenna ports and that are used to demodulate downlink data; and sending, by the network device, the reference signals of the N antenna ports and the downlink data to a terminal device, wherein the reference signals of the N antenna ports comprise cell common reference signals of N 1 antenna ports and reference signals that are of N 2 antenna ports and that are specific to the terminal device, N is an integer greater than or equal to 2 and represents the quantity of layers of the downlink data, N = N 1 + N 2, and N 1 and N 2 are positive integers, further comprising: sending, by the network device, downlink control information to the terminal device, wherein the downlink control information carries a first message and a second message, wherein the first message is used to indicate resources of the reference signals of the N 2 antenna ports in frequency domain, and the second message is used to indicate a value of N, wherein a value of N 2 is indirectly indicated by the second message based on the relationship N=N 1 +N 2, wherein before sending the downlink control information, the method further comprises: scrambling and sending, by the network device, for different values of N 1, data of a physical broadcast channel by using different scrambling codes to indicate to the terminal device the value of N 1 over the physical broadcast channel. generating, by a network device, reference signals that are of N antenna ports and that are used to demodulate downlink data; and sending, by the network device, the reference signals of the N antenna ports and the downlink data to a terminal device, wherein the reference signals of the N antenna ports comprise cell common reference signals of N 1 antenna ports and reference signals that are of N 2 antenna ports and that are specific to the terminal device, N is an integer greater than or equal to 2 and represents the quantity of layers of the downlink data, N = N 1 + N 2, and N 1 and N 2 are positive integers, further comprising: sending, by the network device, downlink control information to the terminal device, wherein the downlink control information carries a first message and a second message, wherein the first message is used to indicate resources of the reference signals of the N 2 antenna ports in frequency domain, and the second message is used to indicate a value of N, wherein a value of N 2 is indirectly indicated by the second message based on the relationship N=N 1 +N 2, wherein before sending the downlink control information, the method further comprises: scrambling and sending, by the network device, for different values of N 1, data of a physical broadcast channel by using different scrambling codes to indicate to the terminal device the value of N 1 over the physical broadcast channel. sending, by the network device, downlink control information to the terminal device, wherein the downlink control information carries a first message and a second message, wherein the first message is used to indicate resources of the reference signals of the N 2 antenna ports in frequency domain, and the second message is used to indicate a value of N, wherein a value of N 2 is indirectly indicated by the second message based on the relationship N=N 1 +N 2, wherein before sending the downlink control information, the method further comprises: scrambling and sending, by the network device, for different values of N 1, data of a physical broadcast channel by using different scrambling codes to indicate to the terminal device the value of N 1 over the physical broadcast channel.