To solve the problem that many temperature fluctuations occur in cold chain logistics from catching to selling Bonito, a new analog cutting system was designed under -18 ℃ environment based on wide-temperature PLC. Results showed that the design was superior to the traditional manual processing under room temperature and mechanical cutting after ultra-low temperature defrosting whether in low-temperature preservation or cutting speed, which reduced the cutting and exposure links and the temperature fluctuations effectively. After being assembled between the processing and quick-frozen cabins of the ocean-going fishing vessel, the synchronization of cutting and quick freezing could be realized, which could provide an effective way to keep fresh for the cold chain logistics of Bonito.