The invention discloses a trigger circuit of a direct light-triggered thyristor. Laser trigger signals are utilized to trigger the thyristor. The trigger circuit comprises a photoelectric conversion circuit, a pulse providing unit, a laser tube unit, a photoelectric isolation circuit and a voltage stabilizing circuit. The photoelectric conversion circuit, the pulse providing unit and the laser tube unit are connected in sequence; the photoelectric isolation circuit is connected with the pulse providing circuit; the voltage stabilizing circuit is used for stabilizing input 24V direct-current voltage into 5V voltage and 2.5V voltage respectively to provide to various electric circuits correspondingly. The trigger circuit having the advantages of good stability, high reliability and long service life can overcome defects such as poor stability, low reliability and short service life of the prior art.