Based on different structures，the dual range pistons can be divided into dual piston pressure vacuum gauges and dual piston gauges. According to the structural characteristics of the dual piston gauge, we analyzed the case when two piston-cylinder systems used only one set of weights. The actual pressure value under nominal value was calculated according to the quality of the weights and the parameters of the piston. The results show that the accuracy grades can be divided according to the different pressure ranges,to achieve the piston gauge traceability calibration and ensure the accuracy and consistency of pressure field.?