The invention provides an uplink transmission feedback method and system, a base station and user equipment. The uplink transmission feedback method comprises the steps that the user equipment transmits uplink data to the base station on an unauthorized spectrum; the user equipment acquires the position of hybrid automatic repeat request feedback in allusion to itself in downlink control signaling or a physical HARQ (Hybrid Automatic Repeat Request) indication channel; the user equipment receives downlink control signaling or a physical HARQ indication channel which is sent by the base station after receiving the uplink data, wherein the downlink control signaling or the physical HARQ indication channel comprises hybrid automatic repeat request feedback in allusion to at least one set of user equipment; and the user equipment parses the hybrid automatic repeat request feedback in allusion to itself from the downlink control signaling or the physical HARQ indication channel according to the position of the hybrid automatic repeat request feedback in allusion to the user equipment in the downlink control signaling or the physical HARQ indication channel. Transmission of the user equipment on the unauthorized spectrum can be fed back accurately according to the invention.