The invention discloses an inner trigger circuit of a gas discharge lamp, comprising a discharge tube and a ballast. The inner trigger circuit is characterized in that a bimetallic strip of a temperature switch of the circuit in the lamp is welded to a lead of the discharge tube at one end of the discharge tube, and a fixed contact of the temperature switch is welded to the lead at the other end of the discharge tube. The problem that the bimetallic strip is burned and damaged when the circuit is over-current previously is solved. The inner trigger circuit is simple and reasonable in structure, can be freely opened and closed, and is safe, reliable, and low in cost. Practice proves that the temperature switch of the inner trigger circuit of the gas discharge lamp is not burned out under any circumstances, the service life of the temperature switch is prolonged to the maximum degree, and the service life of the gas discharge lamp is prolonged. Great convenience is brought to users, and the inner trigger circuit has good economic and social benefits.