When the temperature of the gas flow changes, a synthetic bi-metal with different thermal expansion coefficients on the compensation mechanism will be triggered. The deformation is bended, so the length of the crank will be changed to adjust the movement of the diaphragm. Thereby the cyclic volume is changed. Its special design will counteract the volume differences which caused by the thermal expansion and contraction of gas. This kind of meter could improve environmental adaptability of diaphragm gas meter, and greatly improve the measurement accuracy.