A trapezoidal cantilever density sensor is developed based on micro-electro-mechanical systems （MEMS） technology. The sensor measures fluid density through the relationship between the density and the resonant frequency of the cantilever im-mersed in the fluid. To improve the sensitivity of the sensor, the modal and harmonic response analyses of trapezoidal and rec-tangular cantilevers are simulated by ANSYS software. The higher the resonant frequency of the cantilever immersed in the fluid, the higher the sensitivity of the sensor; the higher the resonant strain value, the easier the detection of the output signal of the sensor. Based on the results of simulation, the trapezoidal cantilever is selected to measure the densities of dimethyl silicone and toluene at the temperature ranges of 30 to 55 ℃ and 26 cantilever density sensor has a good performance. to 34 ℃, respectively. Experimental results show that the trapezoidal cantilever density sensor has a good pertbrmance.
