The invention relates to a blast vibration safety judgment method considering crustal stress transient unloading. The blast vibration safety judgment method includes the steps that 1, a vibration meter is used for carrying out vibration monitoring on an excavated tunnel body and surrounding buildings to obtain actual measurement surrounding rock vibration signals; 2, the actual measurement vibration peak value PPV1 is obtained; 3, blast load (BL) and crustal stress transient unloading (IS) are recognized; 4, vibration amplitudes caused by two excitation source coupling action, crustal stress transient unloading and blast load, corresponding main vibration frequency and frequency demarcation point of blast high-frequency waves and transient low-frequency waves are obtained respectively; 5, the transient vibration peak value PPV2 and the blast vibration peak value PPV3 are obtained; 6, blast vibration safety allowable values [PPV1], [PPV2] and [PPV3] corresponding to the coupling vibration main frequency f1, the transient main frequency f2 and the blast main frequency f3 are selected; 7, the coupling vibration peak value PPV1 and the coupling safety allowable value [PPV1], the crustal stress transient vibration peak value PPV2 and the transient safety allowable value [PPV2] as well as the blast vibration peak value PPV3 and the blast safety allowable value [PPV3] are compared. The blast vibration safety judgment method is capable of accurately and reliably evaluating blast vibration safety.