The invention discloses a high-precision ultrasonic liquid difference identification device for food safety. The identification device comprises two detachable ultrasonic sending and receiving sensors, a signal processing chip, a display screen and a key. The signal processing chip comprises a frequency and power adjustable sending circuit, a receiving circuit which can perform noise reduction, amplification, oversampling and filtering, a sigma-delta AD modulator, an adjustable digital filter circuit, a high-speed memory and a memory access interface thereof, a wireless sending module, a microprocessor and a crystal oscillator. Through use of the identification device, when ultrasonic waves pass through liquids, high-precision extraction of signals can be performed, through comparison of the signal characteristic values corresponding different substances, differences among the substances can be distinguished, and in food safety, fake and poor quality liquid food can be effectively distinguished. At the same time, although a plurality of high-precision signal processing circuits are integrated on one single chip, the chip area is small, so that the identification device is small in volume and portable, and is suitable for personals and families.