Abstract:  As a connecting element in circuit，the conductor wire is indispensable but often neglected． This paper discusses the properties of the ideal conductor wire with zero resistance and the actual conductor wire，and explains the contradiction of the deductions from the properties of the ideal conductor wire． We can take the ideal conductor wire as perfect conductor to understand its properties and take the actual conductor wire as resistor to deal with its role in circuit．

Key words: conductor wire, perfect conductor, resisit