We present a chip-scale optofluidic interferometric sensor for measuring liquid pressure based on an imaging method. The chip was constructed with a polymer by multilayer soft lithography. It consists of a flexible air gap optical cavity, which, upon illumination by monochromatic light, generates interference patterns that depend on pressure. The pressure was measured by imaging and analyzing the interference patterns. We also employed a pattern recognition algorithm that significantly simplified the calculation and enhanced the measurement reliability. This pressure sensor was demonstrated with a working range of 0-22 psi and an accuracy of +/- 1.4% of full scale when temperature stabilized. (C) 2010 Optical Society of America