Literature review
根据本文的研究目的，本文从以下六个方面回顾相关研究：产品差异化战略的内容，产品差异化战略决策模式，产品差异化战略的优势和风险，在产品差异化战略实施的关键点，产品差异化战略和中国的头发护理行业，在这最后，总结了文献提出的批判性分析的研究。
产品差异化策略
产品差别化是指，具有一定的模式，一个企业改变其产品有一定的相似性使消费者相信这些产品是不同的，因此，消费者将有不同的偏好。产品整体概念包括三个层次，即，核心产品，形式产品和延伸产品。产品的差异也可以分为三个层次，即核心产品差异化，产品差异化，产品差异化和扩展形式。
核心产品
核心产品也被称为真正的产品，它指的是核心利益，消费者追求时，他们买某种产品，这就是客户想买真的，它决定了产品的功能和效用。它是产品的整体概念的第一阶段，也是最基本的水平。核心产品的差异化是指企业应当向消费者提供比竞争产品提供更多的效用和利益。企业应根据与他们的竞争对手的产品功能的比较，根据消费者的现实需求和潜在的产品功能，为消费者提供符合消费者需求的产品功能的需求，从而建立比较优势向竞争产品。
Introduction
According to the research aim of this paper, this chapter was from the following six aspects to review relevant researches: contents of product differentiation strategy, decision mode of product differentiation strategy, advantages and risks of product differentiation strategy, key points in implementation of product differentiation strategy, product differentiation strategy and Chinese hair care industry, at the end of this chapter, it concluded the literatures and presented a critical analysis towards the researches.
Product differentiation strategy
Product differentiation refers to that, with certain patterns, an enterprise changes its products which are similar to some extent to make consumers believe that these products are different, so that costumers will have different preference. The overall concept of products includes three levels, namely, core products, formal products and extension products. Product differentiation also consists three levels, namely, core product differentiation, formal product differentiation and extension product differentiation (Caves & Williamson, 1985).
Core product
Core product is also known as real product, it refers to the core interests that consumers pursue when they buy certain product, it is what customers really want to buy, it decides the function and utility of a product. It is the first level of the overall concept of products, it is also the most basic level (Caves & Williamson, 1985). Core product differentiation refers to that enterprises should provide consumers with more utility and benefits than their competitive products provide. Enterprises should be based on the comparison with functions of their competitors’ products, according to consumers’ realistic demand and potential demand for product function to provide consumers with the product function which suits consumers’ demand more, so as to establish comparative advantages towards competitive products (Lee & Tang, 1997).
Formal product
Formal product is also called tangible product, referring to entities of product or appearance of services provided for a market, it is the carrier of core product, it is also the basis for buyers to purchase. It has five signs, namely, quality, characteristic, modality, brand and packaging. Formal product differentiation refers to the differentiation in quality, characteristic, form, packaging and brand of products when compared with competitive products (Caves & Williamson, 1985).
•Product quality differentiation
Quality is the life of an enterprise. Enterprises are through various means of quality control to carry out differentiated management towards stability, durability, reliability and other quality indicators of products to obtain competitive advantages. According to the survey, there is a highly positive correlation between quality of products and investment return, enterprises which produce products of high quality profit 60% more than enterprises which produce products of low quality. The reason for why the former earns more lies in that products of high quality enable the enterprises to sell the products at high prices, and they benefit from more repeat purchase, which enables them get consumers’ loyalty and good reputation (Desai, et al., 2001).). For example, based on its good quality, Procter & Gamble Company (P & G for short) improves its products continuously, thereby enabling the company to take a leading position in many markets.
•Brand differentiation
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