The invention discloses an energy-saving lamp for starting a square wave inverter. The energy-saving lamp comprises a starting template, a detection template, an exception handling template and an energy-saving illumination template, wherein the starting template is connected to the detection template; the detection template is connected with the exception handling template and the energy-saving illumination template respectively; and the exception handling template is connected with the starting template. Through the technology, PWM is used for controlling the operation of a field-effect tubeby using a single-chip microcomputer as a core, and the driving mode of the field-effect tube is adjusted constantly so as to promote the field-effect tube to start the energy-saving lamp in an optimal state; moreover, a peripheral thermistor is used for detecting the temperature of the field-effect tube constantly, and the temperature of the field-effect tube is fed back to the single-chip microcomputer so as to guarantee that the square wave inverter cannot be damaged while greater energy-saving lamp is started; and the single-chip microcomputer is used for control, so that the starting capacity is greatly improved, the cost is not increased, the circuit is simple in structure, and the energy-saving lamp has the advantage of high universality.