The disclosure relates to the field of wireless communications and provides a method for dynamically indicating a Quality of Service (QoS) Flow Identity (ID) (QFI) and User Equipment (UE). The method includes: a UE obtains a Service Data Adaptation Protocol (SDAP) Service Data Unit (SDU) and obtains a first QFI to which the SDAP SDU belongs; maps the first QFI with a relatively large number of bits to a second QFI with a relatively small number of bits, here, a value of the first QFI is mapped to a value of the second QFI which is the same as the value of the first QFI when a value of the first QFI is less than a first preset threshold and the value of the first QFI is mapped to a value of an unmapped vacant position of the second QFI when the value of the first QFI is greater than the first preset threshold; and then includes the second QFI in an SDAP header. Thus, communication service may be implemented better on the basis of an existing communication standard.