The invention relates to a technique method for improving the stability of an NTC thermal resistor chip and belongs to the technical field of the manufacture technique of electronic devices. The technique method comprises the steps of mixing ingredients, ball milling, prepressing forming after drying, isostatic pressing, first sintering, slicing and second sintering. The NTC thermistor ceramic chip is sintered twice in two different process stages to eliminate internal non-equilibrium defects of the NTC thermistor ceramic chip caused by the stress action due to high temperature and machine tooling, and to speed up the stabilization process; meanwhile, a layer of compact sintered molten layer is formed on the surface of ceramic sheets to effectively eliminate the open pores. Thus the invention can significantly improve the stability of the NTC thermal resistor chip to solve the problems that the NTC thermal resistor chip has low stability and bad reliability.