The invention discloses a temperature compensating circuit and method and a liquid crystal display. The temperature compensating circuit and method and the liquid crystal display are applied to a display panel. The temperature compensating circuit comprises a temperature detecting unit, a temperature converting unit and a compensating signal generating unit, wherein the temperature detecting unit is used for detecting a temperature variation, the temperature converting unit is used for converting the detected temperature variation into a voltage compensation variation, and the compensating signal generating unit is used for processing the voltage compensation variation so as to generate a compensating signal used for temperature compensation of the public electrode voltage of the display panel. According to the temperature compensating circuit and method, the public electrode voltage of the display panel can be adjusted in real time when the temperature changes, the public electrode voltage is made to be on the midpoint between positive gray scale change and negative gray scale change, in this way, the number of flickers generated when the polarity of the display panel is reversed is kept the smallest, an image can be displayed more stably, and the visual experience of a viewer is improved.