A method for reporting power headroom in an uplink multi-carrier system including a user equipment and a base station equipment, the system cell uplink including at least two component carriers, CCs, and the user equipment including at least one power amplifier, PA, the method comprising the following steps: judging, by the user equipment, whether power headroom reporting, PHR, is triggered; and reporting, by the user equipment, power headroom independently based on a CC, or independently based on a PA, or associatively based on a plurality of CCs, or associatively based on a plurality of PAs, in response to the PHR being triggered, wherein the reporting, by the user equipment, power headroom independently based on a CC comprises: confirming, by the user equipment, that uplink resources indicated by an uplink, UL, grant in the CC can accommodate the PHR, calculating the power headroom, PH, value of the CC, generating PHR media access control element, MAC CE, according to the PH value, and sending the PHR MAC CE in the uplink resources indicated by the UL grant of the CC which can accommodate the PHR; or the reporting, by the user equipment, power headroom associatively based on a plurality of CCs comprises: confirming, by the user equipment, that the uplink resources indicated by an UL grant of the CC can accommodate PHR of all CCs, calculating the PH values of all CCs, generating PHR MAC CE according to the PH values, and sending the PHR MAC CE in the uplink resources indicated by the UL grant in any one of CCs that can accommodate the PHR; or the reporting, by the user equipment, power headroom independently based on a PA comprises: confirming, by the user equipment, that the uplink resources indicated by an UL grant of the CC supported by the PA can accommodate the PHR of the PA, calculating the PH value of the PA, generating PHR MAC CE according to the PH value, and sending the PHR MAC CE in the uplink resources indicated by the UL grant of the CC which can accommodate the PHR; or the reporting, by the user equipment, power headroom associatively based on a plurality of PAs comprises: confirming, by the user equipment, that the uplink resources indicated by an UL grant of the CC can accommodate PHR of all PAs, calculating the PH values for all PAs, generating PHR MAC CE according to the PH values, and sending the PHR MAC CE in the uplink resources indicated by the UL grant in any one of CCs that can accommodate the PHR, the method characterized in that, the method further comprises: configuring, by the base station equipment, PHR-related parameters for each CC or PA, and informing the user equipment of the PHR-related parameters; and the judging step comprises: judging, by the user equipment, whether there is any one of PHR trigger conditions satisfied according to the PHR-related parameters configured for each CC or PA. judging, by the user equipment, whether power headroom reporting, PHR, is triggered; and reporting, by the user equipment, power headroom independently based on a CC, or independently based on a PA, or associatively based on a plurality of CCs, or associatively based on a plurality of PAs, in response to the PHR being triggered, wherein the reporting, by the user equipment, power headroom independently based on a CC comprises: confirming, by the user equipment, that uplink resources indicated by an uplink, UL, grant in the CC can accommodate the PHR, calculating the power headroom, PH, value of the CC, generating PHR media access control element, MAC CE, according to the PH value, and sending the PHR MAC CE in the uplink resources indicated by the UL grant of the CC which can accommodate the PHR; or the reporting, by the user equipment, power headroom associatively based on a plurality of CCs comprises: confirming, by the user equipment, that the uplink resources indicated by an UL grant of the CC can accommodate PHR of all CCs, calculating the PH values of all CCs, generating PHR MAC CE according to the PH values, and sending the PHR MAC CE in the uplink resources indicated by the UL grant in any one of CCs that can accommodate the PHR; or the reporting, by the user equipment, power headroom independently based on a PA comprises: confirming, by the user equipment, that the uplink resources indicated by an UL grant of the CC supported by the PA can accommodate the PHR of the PA, calculating the PH value of the PA, generating PHR MAC CE according to the PH value, and sending the PHR MAC CE in the uplink resources indicated by the UL grant of the CC which can accommodate the PHR; or the reporting, by the user equipment, power headroom associatively based on a plurality of PAs comprises: confirming, by the user equipment, that the uplink resources indicated by an UL grant of the CC can accommodate PHR of all PAs, calculating the PH values for all PAs, generating PHR MAC CE according to the PH values, and sending the PHR MAC CE in the uplink resources indicated by the UL grant in any one of CCs that can accommodate the PHR, the method characterized in that, the method further comprises: configuring, by the base station equipment, PHR-related parameters for each CC or PA, and informing the user equipment of the PHR-related parameters; and the judging step comprises: judging, by the user equipment, whether there is any one of PHR trigger conditions satisfied according to the PHR-related parameters configured for each CC or PA.