An instrument for the automatic determination and recording of water levels in water bodies such as rivers, lakes and irrigation canals. According to the principle of the sensor split float type, tracking type, pressure type and reflection type and so on. The main methods of water level recording are: recording paper description, data display or typing record, perforated tape, tape and solid circuit storage, etc. The accuracy of the water level meter is generally within 1~3 cm, and the recording period of the water level meter made in China is 1 days, 30 days and 90 days. Timing error, mechanical clock is 2 minutes/day, quartz crystal clock less than 5 minutes/month.