The standard deviation analysis method is crucial for effectively evaluating radar data quality. This study applies the standard deviation analysis to analyse the polarisation parameters of C-band dual-polarisation radar, identifying the main influencing factors and optimising parameter configurations. The improvement effects on the standard deviation of polarisation parameters across typical weather processes are examined through observational experiments. The findings indicate that the accuracy of existing observational modes for C-band polarisation parameters is relatively low, with significant discrepancies in accuracy across different elevation angles. Specifically, the accuracy of polarisation parameter data at 1.5° elevation is higher than that at 0.5°. The dwell time, pulse repetition frequency, and number of pulses directly impact the standard deviation of C-band dual-linear polarisation radar’s polarisation parameters. By optimising the pulse repetition frequency and number of pulses, the accuracy of polarisation standard deviation is enhanced without altering the observational mode within the same dwell time. An analysis of the standard deviation of polarisation parameters during two typical weather processes reveals that, before parameter optimisation, the accuracy of polarisation standard deviation is generally higher during hail processes than in heavy precipitation events. However, post-improvement, the enhancement in the accuracy of polarisation standard deviation for heavy precipitation events is usually superior to that for hail events. The modified observational mode thus improves the accuracy of polarisation parameter data for C-band dual-polarisation radar to a certain extent.