在进行流程优化设计时，流程的分类是头疼的问题，基于价值链（value chain） 进行的分类，是常用的一种分类方法。
在90年代中期，麦肯锡提出了core business process 的概念，所谓core business process 指导向客户端的流程，是价值链中直接提供企业增值的部分，因此也是流程优化的重点。但企业作为整体发挥作用，除了核心业务流程外，其他的流程同样具有重要的作用，不进行优化必然与已经优化的核心业务流程产生冲突，怎样界定其他的企业流程成为研究流程的关键。
有的学者提出了一二三级流程的概念，但对流程分级概念理解不统一，认为价值链为一级流程，支撑系统为二级流程，工作程序为三级流程，从流程范围看，这样的分类似乎是合理的，但从企业运作系统看，这样的分类无法界定流程的范围及流程涵盖的职能区域。有的文献对流程分类顾问认为更适合在流程优化项目中使用，其对流程的分类界定如下：
Primary processes are those that produce the company’s products or services. They therefore are known also as production processes. They deal with cases for the customer. As a rule, they are the processes that generate income for the company, and are clearly customer-oriented. Sometimes the customer is not yet known, as when firms produce to stock. Examples of primary processes are the purchase of raw materials and components, the sale of products and services, design and engineering, and production and distribution.
Secondary processes are those that support the primary ones. They therefore are also known as support processes. One important group of secondary processes concentrates upon maintaining the means of production: the purchase and maintenance of machinery, vehicles, and premises. A comparable group of processes is that involving personnel management: recruitment and selection, training, work appraisal, pay rolls, and dismissal. Financial administration is also a secondary process, as is marketing.
Tertiary processes are the managerial processes that direct and coordinate the primary and secondary processes. During these, the objectives and preconditions within which the managers of the other processes must operate are formulated, and the resources required to carry out the other processes are allocated. The managerial processes also encompass the maintenance of contacts with financiers and other stakeholders.
采用这样的流程分类方法，在流程优化项目的建议书阶段，与客户商讨确定流程优化的范围，同时在流程优化项目中，采用这样的流程分类更有利于形成企业整体的流程体系。
