Based on the grey system theory

the stability evaluation of manufacturing system could be put into effect via grey relation analysis of the two data series in the manufacturing process. According to these two data sequences obtained in the manufacturing process with certain property

the data series could be sorted

so the sorting data figure was achieved. The grey relation between two data series was established by means of the distribution features of sorting data figure. And the stability evaluation of manufacturing process can be realized through calculation and analysis of the grey confidence level. Computer simulation experiment and actual case indicate that through analyzing the grey relation of two data series

if the grey confidence level is not less than 90%

the manufacturing system is stable; otherwise

the manufacturing system is not stable. The method proposed is very good at testing the stability of the manufacturing system

with accuracy up to 100%.