This paper deeply researches gas-pendulum theory and characteristic, and detailedly explains the character that micro-machined gas-pendulum tilt sensors can not only measure obliquity but also linear acceleration. This paper finds out the relation of sensing mechanism of micro-machined gas-pendulum sensors measuring obliquity and acceleration. According to the different principles between gas-pendulum accelerometers and other accelerometers which measure obliquity basing on components of acceleration due to gravity on two orthogonal axes, the paper puts forward the concept of common-mode restraining, discusses the basic principle and implementation scheme of the micro-machined gas-pendulum dual-axis tilt sensors common-mode restraining acceleration interference, primarily simulates them and has a test.