Recently,the integrated pressure,temperature,and relative humidity sensor with high precision are highly needed in environmental monitoring and industrial control.The challenge of this kind of sensor is that both the high precision of each sensor and the compatibility of the sensor fabrication should be ensured.Based on MEMS technology,we designed and fabricated a high precision integrated pressure,temperature,and relative humidity sensor.The 7.0× 3.5 ×0.8mm3 sensor chip consists of a capacitive humidity sensor,a pressure sensor and a Pt resistance temperature sensor.The humidity sensor is composed of capacitance electrodes and a polyimide film as the sensitive material.The pressure sensor has a silicon membrane with platinum piezoresistors and is sealed by adhesive bonding with SU-8.The humidity sensor shows a wide range of sensing ambient relative humidity and has a precision of ±3RH%.The precision of the pressure sensor is high with a linearity of 0.2% and a square fit of 0.05%.