Silicon resonant pressure sensors are widely used in aerospace and industry due to high accuracy, good linearity, and long-term stability. Due to the stress and signal processing limitation, its accuracy is difficult to meet the application requirements, and we can only search methods to approach this continuously. This research introduces a stress-isolated structure and a processing method of frequency signal to enhance the index. The stress-isolated structure separates press-sensor from printed circuit board by nested bonding for plates by silica gel. It minimizes the transmitted stress but no affection on electrical connection. The analysis algorithm of frequency based on given waveform number instead of given time improves the analytical accuracy of frequency and pressure. By redesigning interrupt timing control strategy in Microcontroller unit, it addresses sudden jumps of frequency signal. The proposed technique, tested on a resonant pressure sensor at temperature condition of -45°C to 75°C and barometric condition of 3.5kPa to 110kPa, reduces the effect of stress effectively, and enhances to 0.02Hz in accuracy of frequency. More importantly there is no sudden jump in frequency signal. The pressure accuracy outperforms 0.0145% after calibrating. Over all, the advised method meets the requirement of high accuracy and promotes applications in aerospace field.