A beam indication method and apparatus and a system. The method includes: receiving activation signaling by a terminal equipment, the activation signaling activating at least one transmission; and transmitting or receiving the at least one transmission by the terminal equipment based on an understanding that: before receiving deactivation signaling or a next time of activation signaling, all transmissions activated by the activation signaling use identical spatial domain filters or transmission hypotheses, or use respective spatial domain filters or transmission hypotheses determined by dynamically interpreting the activation signaling. For a semi-persistently scheduled or periodically scheduled transmission, between activation signaling and deactivation signaling or a next time of activation signaling, identical spatial domain filters or transmission hypotheses or respective spatial domain filters or transmission hypotheses determined by dynamically interpreting the activation signaling are used for transmission or reception, thereby solving the problem of ambiguity of beam indication in the above time period.