The invention discloses a resonant
tuning fork liquid density sensor with piezoelectric actuation and piezoelectric detection, comprising a
tuning fork body, a clamped body, a piezoelectric
actuator, a piezoelectric vibration
pickup, and a temperature sensor, wherein, the piezoelectric
actuator and the piezoelectric vibration
pickup are arranged on the clamped body, the generated alternating force is transmitted to the
tuning fork body by the piezoelectric
actuator to let the tuning fork body produce simple
harmonic vibration with intrinsic frequency itself; when immersing the tuning fork body in a liquid under test, the additional
mass of the tuning fork body changes so as to let the vibration frequency of the tuning fork body change; by picking up the vibration
signal with the piezoelectric vibration
pickup, the detection of the vibration frequency of the tuning fork body is realized; because the vibration frequency of the tuning fork body is a monotone function of the
liquid density, thus the real-time on-line detection of the
liquid density is realized; and the temperature sensor is arranged on the clamped body for real-time detection of the temperature of the liquid under test, and is used for compensating the variation of the
elastic modulus of the tuning fork body. According to the invention, the high precision on-line detection of densities of various liquids at different temperature can be realized.