Disclosed is a method of realizing a dual mode acoustic wave sensor capable of being operated in both a gas environment and a liquid environment in a single chip by disposing a surface acoustic wave filter and a surface skimming bulk wave filter perpendicular to each other on the same wafer using the peculiar cut-orientation of an piezoelectric element, i.e. ST-cut quartz. An acoustic wave biosensor can realize optimum detection performance by detecting the characteristics of a detection environment and a detection target in real time during the operation of a dual mode sensor, and automatically switching between an SAW mode and an SSBW mode.