According to the problem that exists in the simple digit accumulation method of the cutting tool life , this paper put forward the conception of equivalent life of cutting tool. And the mathematics model of cutting tool life was founded based on the conception. Therefore, the actual wear value of cutting tool can be well reflected. Based on the Labview, the tool life offline prediction software and tool life on-line prediction software were developed to provide theoretical basis of calculating tool life for cutting tool requirement planning, cutting tool cost accounting and the planning of the cutting parameters.