In the wireless sensor network, the nature of sensor nodes has a direct impact on the network life cycle. In order to improve the energy efficiency of nodes and extend the network lifetime, WSN acquisition nodes are studied. SAW based on a micro force sensor is used as a sensor node, and the frequency and pressure transformation model of SAW sensors is established by the principle of least squares method. According to the model, polyfit function and matrix calculation are selected to solve and calculate the polynomial coefficients. The data acquisition of WSN nodes were simulated and polynomial curve fitting was drawn. The actual SAW sensor is tested to demonstrate the rationality of device stability in WSN.