Abstract: Capacitance diaphragm gauges are widely used to measure medium and low vacuum. To improve the measurement accuracy of capacitance diaphragm gauges, the algorithm is applied to the data processing of capacitance diaphragm gauges. The piecewise fitting method can make the error data curve on each data segment fit more accurately according to the characteristics of the data on each data segment. However, this approach has the problem of data point jumping at boundary points, which has a great impact on practical use. In this paper, a data processing algorithm based on fuzzy control theory is designed to eliminate the problem of the hopping gap at the cut-off point of barometric pressure measurement. After the processing of the fuzzy control algorithm, the measurement accuracy of the capacitance diaphragm gauge is improved, and the barometric pressure measurement data curve has good continuity in the whole range.