The present invention provides a method and an apparatus of implementing beam tracing in a millimeter wave communication-based communication system. According an embodiment of the present invention, the method comprises: traversing ail precoding matrixes to calculate a channel capacity for a beam; selecting n precoding matrixes from the precoding matrixes, wherein the channel capacity calculated by using the n precoding matrixes is the top n maximum channel capacity in ail the calculated channel capacity; determining an amplitude vector, the amplitude vector consists of n channel performance indicators corresponding to the top n maximum channel capacity respectively; and sending n precoding matrix indicators corresponding to the n precoding matrixes and the amplitude vector to the base station. Through the present invention, multiple mobile user equipments can be supported with a high data rate in 5 G MMC networks.