An Acknowledge/Not Acknowledge, ACK/NACK, information feedback method, comprising: sending, by a terminal device, uplink data to a network side device; receiving, by the terminal device, first Downlink Control Information, DCI, sent by the network side device, the first DCI comprising an ACK/NACK information sequence, the ACK/NACK information sequence being formed by multiple pieces of ACK/NACK information corresponding to the uplink data; and determining, by the terminal device, position information of the multiple pieces of ACK/NACK information corresponding to the uplink data; the method further comprising: determining, by the terminal device, the multiple pieces of ACK/NACK information corresponding to the uplink data in the ACK/NACK information sequence according to the position information, wherein determining, by the terminal device, the multiple pieces of ACK/NACK information corresponding to the uplink data in the ACK/NACK information sequence according to the position information comprises: when the position information is an index of a first bit of each piece of ACK/NACK information corresponding to the uplink data in all bits of the ACK/NACK information sequence, determining, by the terminal device, the first bit of each piece of ACK/NACK information corresponding to the uplink data in the ACK/NACK information sequence according to the index; and determining, by the terminal device, remaining bits of each piece of ACK/NACK information corresponding to the uplink data in the ACK/NACK information sequence according to a number of bits contained in each piece of ACK/NACK information corresponding to the uplink data; determining, by the terminal device, position information of the multiple pieces of ACK/NACK information corresponding to the uplink data according to one of: indication information sent to the terminal device by the network side device, scheduling information for the network side device to schedule the terminal device to send the uplink data. sending, by a terminal device, uplink data to a network side device; receiving, by the terminal device, first Downlink Control Information, DCI, sent by the network side device, the first DCI comprising an ACK/NACK information sequence, the ACK/NACK information sequence being formed by multiple pieces of ACK/NACK information corresponding to the uplink data; and determining, by the terminal device, position information of the multiple pieces of ACK/NACK information corresponding to the uplink data; the method further comprising: determining, by the terminal device, the multiple pieces of ACK/NACK information corresponding to the uplink data in the ACK/NACK information sequence according to the position information, wherein determining, by the terminal device, the multiple pieces of ACK/NACK information corresponding to the uplink data in the ACK/NACK information sequence according to the position information comprises: when the position information is an index of a first bit of each piece of ACK/NACK information corresponding to the uplink data in all bits of the ACK/NACK information sequence, determining, by the terminal device, the first bit of each piece of ACK/NACK information corresponding to the uplink data in the ACK/NACK information sequence according to the index; and determining, by the terminal device, remaining bits of each piece of ACK/NACK information corresponding to the uplink data in the ACK/NACK information sequence according to a number of bits contained in each piece of ACK/NACK information corresponding to the uplink data; determining, by the terminal device, position information of the multiple pieces of ACK/NACK information corresponding to the uplink data according to one of: indication information sent to the terminal device by the network side device, scheduling information for the network side device to schedule the terminal device to send the uplink data. determining, by the terminal device, the multiple pieces of ACK/NACK information corresponding to the uplink data in the ACK/NACK information sequence according to the position information, wherein determining, by the terminal device, the multiple pieces of ACK/NACK information corresponding to the uplink data in the ACK/NACK information sequence according to the position information comprises: when the position information is an index of a first bit of each piece of ACK/NACK information corresponding to the uplink data in all bits of the ACK/NACK information sequence, determining, by the terminal device, the first bit of each piece of ACK/NACK information corresponding to the uplink data in the ACK/NACK information sequence according to the index; and determining, by the terminal device, remaining bits of each piece of ACK/NACK information corresponding to the uplink data in the ACK/NACK information sequence according to a number of bits contained in each piece of ACK/NACK information corresponding to the uplink data; determining, by the terminal device, position information of the multiple pieces of ACK/NACK information corresponding to the uplink data according to one of: indication information sent to the terminal device by the network side device, scheduling information for the network side device to schedule the terminal device to send the uplink data.