4P theory has dominated the marketing field for more than 31 years. With the development of economy and the change of market environment, and there are some problems in the practice of 4P in enterprises, western marketing scholars constantly modify and expand the marketing mix factors with 4P as the core. Most of these changes and extensions are "4P plus one or more P".

in the 1971s, the service industry developed rapidly. Service marketing is different from the traditional 4P product marketing. In order to overcome this theoretical defect, Booms and Bitner added three "service P's" on the basis of the original 4P in 1981:

Participants (some scholars also call them People, that is, employees who are service providers and customers who participate in the service process).

PhysicalEvidence (the environment of service organization and all tangible substances used in the Process of service production and communication with customers) and

process (the procedure, mechanism, activity flow of service production and the interaction and contact communication with customers), thus forming the 7P of service marketing.

correspondingly, gronlos also advocates that service marketing needs not only traditional 4P external marketing, but also internal marketing and interactive marketing. He believes that external marketing refers to the routine work such as service, pricing, distribution and promotion prepared by the company for customers.

internal marketing means that the service company must cultivate and encourage the personnel who directly receive customers and all the auxiliary personnel to make them cooperate with each other in order to satisfy customers. Every employee must implement customer orientation, otherwise it is impossible to improve the service level and stick to it consistently.

interactive marketing refers to the skills of employees when dealing with customers. Service quality is inseparable from service providers. Customers evaluate service quality not only according to their technical quality, but also according to their functional quality. Especially, before customers buy services, they judge the service quality more by price, personnel and material facilities.

Although the theory of p>7P is based on the particularity of service marketing and expanded and developed on the basis of 4P, it has been criticized by some marketing scholars. According to Walter Van Waterscott, strictly speaking, the three "P's" added can either be found in 4P or not belong to the marketing mix variables. In the case of service marketing, participants can improve or damage the service effect to a great extent. However, the personal activities of performing services belong to the first "P" < P”

(Product), which actually includes the production process of products whose purpose is to meet the needs, and employees' participation in the production process is the proper meaning of the marketing combination element "product P". It is the innovation of 7P to regard customers as participants in the whole marketing activities, but customers themselves do not constitute the elements of marketing mix by definition, and they are only the satisfaction goals of marketing activities. The physical environment of services and tangible elements used to support services can obviously affect demand, but when these elements are under the control of marketers, they are actually part of products or distribution elements. As marketing combination elements, it is not necessary to list them separately. Therefore, for "process P", the process of 4P implementation and realization is the process of meeting customers' needs.