A method for triggering an aperiodic sounding reference symbol, a base station and a user equipment. Including not releasing by a user equipment a resource used for transmitting an aperiodic sounding reference symbol configured by a base station for the user equipment, if the user equipment desynchronizes or the user equipment fails to transmit a scheduling request to the base station; executing a random access procedure by the user equipment; and transmitting by the user equipment the aperiodic sounding reference symbol on the unreleased resource used for transmitting an aperiodic sounding reference symbol configured by a base station for the user equipment according to indication information issued by the base station for indicating the user equipment to transmit an aperiodic sounding reference symbol if the random access succeeds.