The embodiment of the invention provides water-level measuring equipment for a water box and a method thereof and a steam furnace, and belongs to the field of household appliances. The water-level measuring equipment comprises a circuit board, one or more detection capacitance plates arranged on the other side of the circuit board and vertically arranged, a reference capacitance plate arranged onthe circuit board and a detection device, wherein one side of the circuit board fits the inner surface of the side wall of a water-box installing part; detection capacitors are composed of all detection capacitance plates and the ground respectively; a reference capacitor is composed of the reference capacitance plate and the ground; the detection device is used for detecting detection voltage atthe two ends of each capacitor and reference voltage at the two ends of the reference capacitor and outputting water or anhydrous indicator signals for indicating corresponding positions between the water box and each detection capacitor according to each detection voltage and the reference voltage. According to the water-level measuring equipment, non-contact water-level measuring can be achieved, and damage caused when all the parts are splashed with water or impacted is prevented.