The invention discloses a liquid level detection method and a liquid level detection device. The liquid level detection method includes the following steps: detecting a current capacitance of each capacitance detector of N capacitance detectors, wherein the N capacitance detectors are constructed into M capacitance detection units, each capacitance detection unit includes two capacitance detectors, and the N and the M are integers greater than 1; acquiring capacitance variation of each capacitance detector according to the current capacitance of each capacitance detector, and acquiring a capacitance variation difference of each capacitance detection unit according to the capacitance variation of each capacitance detector; and generating liquid level information according to the capacitancevariation difference of each capacitance detection unit. The liquid level detection method and the liquid level detection device can improve the accuracy of capacitance detection, can improve the precision of liquid level detection, has excellent resistance to environment change such as temperature drift, power supply shaking, and PCB noise, and can be used in complex environments.