Abstract: The proposition that 1% error can result in 100% error has been controversial.By analyzing some instances,it brings forward some new concepts based on the error-eliminating theory and system theory,such as the important subsystem,the key subsystem,the key subsystem chain,and so on.Furthermore,the laws as well as the relationship between the system error and subsystems or elements are studied.The ways of eliminating errors in the system are also researched.

Key words: error； systematic mechanism； important subsystem； key subsystem； key subsystem chain；