Abstract:The current effective national standard Vernier, GB/T21389-2008《Vernier,dial and digital display calipers》, only includes traditional vernier, digital display and digital display calipers, but there is still a new form of soft vernier calipers in the measurement industry. Soft vernier calipers are mainly used in the construction industry to measure the diameter or length of prestressed steel cylinder concrete pipes and large pipes. The current metrological verification regulation JJG30-2012 《Current Calipers》 only includes the verification methods for traditional calipers, but it is not applicable to the calibration of soft vernier calipers. This paper presents a calibration method for soft vernier calipers, and analyzes the uncertainty of the calibration results, which solves the problem that the soft vernier calipers cannot be traced.