Different from cryptography encryption, physical-layer encryption(PLE) can provide a higher level of data security by adjusting a structure of signal, and the process of adjustment serves as the key. Based on vector perturbation, a multi-dimensional PLE is proposed in this paper, which is performed to change the structure of signal transmitted in time and frequency domains by introducing a set of phase perturbation sequences as a secret key. This key sequence utilizes a phase-shift property of rotation factor, which never changes the spectral structure of the original signal and prevents SNR loss. Furthermore, an impact of encryption by time and frequency vector perturbation is analyzed on constellation. To ensure the peak to average ratio (PAR) of encrypted waveforms, a circular constellation with a certain width is developed. Verified by simulations, the proposed scheme has no impact on the detection performance of the collaborative receiver.