A method performed by a terminal device, the terminal device communicating with a network device, for determining a measurement gap, the method comprising: determining, by the terminal device, whether measurement of a first signal needs a measurement gap based on a sub-carrier spacing of the first signal and a positional relationship between the first signal and a first bandwidth part BWP, wherein the first BWP is an active BWP of a serving cell, and the first signal is a reference signal sent by a target cell, wherein a center frequency point of the first signal is different from a center frequency point of a second signal, and a sub-carrier spacing of the second signal is the same as a sub-carrier spacing of the first BWP; and the second signal is a reference signal sent by the serving cell, wherein the determining, by the terminal device, whether the measurement of the first signal needs the measurement gap based on the sub-carrier spacing of the first signal and the positional relationship between the first signal and the first BWP, comprises: if the first signal is within the first BWP, and the sub-carrier spacing of the first signal is different from the sub-carrier spacing of the first BWP, the measurement of the first signal does not need the measurement gap, wherein, in a case where a frequency domain position of the first signal belongs to a FR1, if simultaneous reception of the first signal and data is not supported by the terminal device, there is a transmission restriction for the terminal device within a first time range, wherein the first time range is determined based on a time domain position of the first signal; or in a case where a frequency domain position of the first signal belongs to a frequency range FR2, there is a transmission restriction for the terminal device within a first time range, wherein the first time range is determined based on a time domain position of the first signal. determining, by the terminal device, whether measurement of a first signal needs a measurement gap based on a sub-carrier spacing of the first signal and a positional relationship between the first signal and a first bandwidth part BWP, wherein the first BWP is an active BWP of a serving cell, and the first signal is a reference signal sent by a target cell, wherein a center frequency point of the first signal is different from a center frequency point of a second signal, and a sub-carrier spacing of the second signal is the same as a sub-carrier spacing of the first BWP; and the second signal is a reference signal sent by the serving cell, wherein the determining, by the terminal device, whether the measurement of the first signal needs the measurement gap based on the sub-carrier spacing of the first signal and the positional relationship between the first signal and the first BWP, comprises: if the first signal is within the first BWP, and the sub-carrier spacing of the first signal is different from the sub-carrier spacing of the first BWP, the measurement of the first signal does not need the measurement gap, wherein, in a case where a frequency domain position of the first signal belongs to a FR1, if simultaneous reception of the first signal and data is not supported by the terminal device, there is a transmission restriction for the terminal device within a first time range, wherein the first time range is determined based on a time domain position of the first signal; or in a case where a frequency domain position of the first signal belongs to a frequency range FR2, there is a transmission restriction for the terminal device within a first time range, wherein the first time range is determined based on a time domain position of the first signal. if the first signal is within the first BWP, and the sub-carrier spacing of the first signal is different from the sub-carrier spacing of the first BWP, the measurement of the first signal does not need the measurement gap, wherein, in a case where a frequency domain position of the first signal belongs to a FR1, if simultaneous reception of the first signal and data is not supported by the terminal device, there is a transmission restriction for the terminal device within a first time range, wherein the first time range is determined based on a time domain position of the first signal; or in a case where a frequency domain position of the first signal belongs to a frequency range FR2, there is a transmission restriction for the terminal device within a first time range, wherein the first time range is determined based on a time domain position of the first signal.