The present invention provides a data stream processing method, device, and system. The data stream processing method includes: using a precoding parameter to perform precoding processing on an lth to-be-sent data stream of a current kth transmitting device, where the lth to-be-sent data stream includes a lattice point data stream mapped to a lattice grid; and sending the precoded lth to-be-sent data stream to a kth receiving device, where both l and k are positive integers. The technical solutions in the embodiments of the present invention can be helpful for filtering out interference, exactly complies with an actual processing procedure of an interfering data stream, and have strong practicability.