A method of determining whether to transmit a Hybrid Automatic Repeat reQuest ACKnowledge, HARQ-ACK, message, wherein the method comprises: when a physical downlink channel is received before Bandwidth Part, BWP, switching and HARQ-ACK for the physical downlink channel needs to be fed back after the BWP switching, determining, according to a preset rule, whether to transmit the HARQ-ACK for the physical downlink channel after the BWP switching, characterized in that determining, according to the preset rule, whether to transmit the HARQ-ACK for the physical downlink channel after the BWP switching comprises one of following 1), 2), or 3): 1) in a case that the BWP switching occurs on a carrier not used to transmit a physical uplink control channel, PUCCH, transmitting the HARQ-ACK for the physical downlink channel after the BWP switching; 2) in case of Frequency Division Duplex, FDD, in a case that the BWP switching is downlink, DL, BWP switching, transmitting the HARQ-ACK for the physical downlink channel after the BWP switching; or 3) when the BWP switching occurs on a carrier used to transmit a physical uplink control channel, PUCCH, or when the BWP switching occurs on a carrier used to transmit a PUCCH and the BWP switching is uplink, UL, BWP switching in case of FDD, or when the BWP switching occurs on a carrier used to transmit a PUCCH in case of TDD, not transmitting the HARQ-ACK for the physical downlink channel through a PUCCH after the BWP switching, or not transmitting the HARQ-ACK for the physical downlink channel through a PUCCH alone after the BWP switching, or after the BWP switching, transmitting the HARQ-ACK for the physical downlink channel on an uplink channel determined according to a PDCCH indicating the BWP switching, or according to a PDCCH transmitted after the BWP switching is completed, or according to a PDCCH transmitted after a point of the BWP switching. 1) in a case that the BWP switching occurs on a carrier not used to transmit a physical uplink control channel, PUCCH, transmitting the HARQ-ACK for the physical downlink channel after the BWP switching; 2) in case of Frequency Division Duplex, FDD, in a case that the BWP switching is downlink, DL, BWP switching, transmitting the HARQ-ACK for the physical downlink channel after the BWP switching; or 3) when the BWP switching occurs on a carrier used to transmit a physical uplink control channel, PUCCH, or when the BWP switching occurs on a carrier used to transmit a PUCCH and the BWP switching is uplink, UL, BWP switching in case of FDD, or when the BWP switching occurs on a carrier used to transmit a PUCCH in case of TDD, not transmitting the HARQ-ACK for the physical downlink channel through a PUCCH after the BWP switching, or not transmitting the HARQ-ACK for the physical downlink channel through a PUCCH alone after the BWP switching, or after the BWP switching, transmitting the HARQ-ACK for the physical downlink channel on an uplink channel determined according to a PDCCH indicating the BWP switching, or according to a PDCCH transmitted after the BWP switching is completed, or according to a PDCCH transmitted after a point of the BWP switching. not transmitting the HARQ-ACK for the physical downlink channel through a PUCCH after the BWP switching, or not transmitting the HARQ-ACK for the physical downlink channel through a PUCCH alone after the BWP switching, or after the BWP switching, transmitting the HARQ-ACK for the physical downlink channel on an uplink channel determined according to a PDCCH indicating the BWP switching, or according to a PDCCH transmitted after the BWP switching is completed, or according to a PDCCH transmitted after a point of the BWP switching.