A wireless communication system and a method for detecting downlink receiving power in the system are disclosed. N cells in the system respectively transmit data to at least one receiving terminal via N resource blocks using the same time-frequency resources; multiple channel state information reference signals (CSI-RSs) of a corresponding cell are set in each resource block, and orthogonality is maintained among the CSI-RSs of all the cells, wherein N is an integer greater than 1. Said method includes: an additional demodulation reference signal (DM-RS) used for indicating a receiving power is set in a puncture position in the resource block of the first cell which corresponds to a CSI-RS set in a resource block of another cell; and the receiving power of said first cell is detected according to said additional DM-RS. By using said method, the receiving power of a single cell in N cells can be detected, and the system overhead is not increased.