A level conversion circuit including a first level shifter and a second level shifter is provided. The first level shifter converts a first control voltage into a second control voltage during a voltage conversion period. The second level shifter is coupled to the first level shifter. The second level shifter converts the second control voltage into a third control voltage during the voltage conversion period to control a next stage circuit. The first level shifter is configured to detect a voltage level of a power domain where the third control voltage operates and generate a plurality of middle voltages based on the detection result. The second level shifter is configured to generate the third control voltage based on the middle voltages. Furthermore, a voltage level conversion method is also provided.