Temperature characteristic of platinum piezoresistive atmosphere pressure sensor is studied in this paper, in which platinum is used as the sensing material and SU-8 is used as adhesive bonding layer. Normally, temperature variation will bring on resistance change of sensing platinum resistor with a linear relationship. Simultaneously, the thermal expansion mismatching in different material will also change the resistance. They both affect the temperature characteristic of sensor. Based on elasticity theory, the relationship between resistance change and thermal expansion mismatching is analyzed and is not linear. Sum of two parts resistance change is still nonlinear. Because the output of atmosphere pressure sensor is proportional to resistance change, relationship between output and temperature change is also nonlinear. The analysis is consistent with the experimental results.