To make up for the limitation that the traditional interference alignment can only align the signal in one dimensional domain

a novel joint time-frequency interference alignment scheme was put forward in the frequency-selective Gaussian interference channel（GIC）.After the frequency-selective GIC was changed into a set of parallel GICs

a set of time-frequency alignment matrices were employed which aligned the interference signal not only in time domain but also in frequency domain.An algorithm for calculating the time-frequency alignment matrices was presented based on the convex optimization.Computer simulations show that the joint time-frequency interference alignment can obtain the same performance as the traditional interference alignment while the joint time-frequency interference alignment can shorten the decoding time or reduce the occupation of the frequency resource.The joint time-frequency interference alignment scheme is an extension of the traditional interference alignment and provides a more flexible resource allocation approach between time domain and frequency domain.