Voltage contrast(VC) is a popular method for failure site isolation. After study we find some weakness on tradition voltage contrast. This paper presents a new voltage contrast procedure that can conquer the weakness. For a CMOS technology, there are four kinds of contact node were used. They are N+/PW node, P+/NW node , poly gate node and well node. Traditional voltage contrast condition uses constant SEM primary energy like 1KV can not distinguish these four kinds of node well. For example a contact lead to P+/NW will be bright in tradition VC, but a contact connected to well will also be bright. It means tradition VC can not distinguish difference between contact lead to P+/NW and contact lead to well. To improve the weakness of the traditional VC, we will present a new Voltage Contrast technique, which could distinguish all contact types in CMOS technology.