The present disclosure discloses a method for measuring relaxation time of ultrashort echo time magnetic resonance fingerprinting. In the method, semi-pulse excitation and semi-projection readout are adopted to shorten echo time (TE) to achieve acquisition of an ultrashort T2 time signal; and image acquisition and reconstruction are based on magnetic resonance fingerprint imaging technology. A TE change mode of sinusoidal fluctuation is introduced, so that distinguishing capability of a magnetic resonance fingerprint signal to short T2 and ultrashort T2 tissues is improved, and multi-parameter quantitative imaging of the short T2 and ultrashort T2 tissues and long T2 tissues is realized. Non-uniformity of a magnetic field is modulated into phase information of the fingerprint signal through the TE of the sinusoidal fluctuation; a B0 graph is directly reconstructed according to an amplitude-modulated signal demodulation principle; and the phase change caused by a B0 field is compensated in the fingerprint signal.