The present invention discloses a method, an apparatus, an optical component and an optical network system for controlling an operating temperature of an optical component. The method includes: acquiring an external ambient temperature of the optical component; setting a target control temperature of a temperature controller according to the external ambient temperature, where the target control temperature is a function value of the external ambient temperature, and the target control temperature is within a range from an operating temperature lower limit of a laser to an operating temperature upper limit of the laser; and controlling, according to the target control temperature, an operating temperature of the optical component by means of heating or cooling by using the temperature controller.