【正文】 uity is defined as the main concern in brand management and IMC campaign. Every marketer should pursue the long term equity and pay attention to every strategy in detail. Because a small message dissonance would cause great failure of brand extension. On the other hand, consumer has his psychology process in mind. The moderating variable is a useful indication to evaluate consumer evaluation of brand extension. Throughout the categorisation theory and associative work theory, consumer does have the ability to process information into useful knowledge for them. They would measure and pares the difference between core brand and extension product through quality of core brand, fit in category, former experience and knowledge, and difficulty of making. Consequently, in this article may conclude some points about consumer evaluation of brand extension: 1. Quality of core brand creates a strong position for brand and low the impact of fit in consumer evaluation. 2. Similarity between core brand and extension is the main concern of consumer perception of fit. The higher the similarity is the higher perception of fit. 3. Consumer’s knowledge and experience affect the evaluation before extension product trail. 4. The more innovation of extension product is, the greater positive fit can perceive. A successful brand message strategy relies on a congruent munication and a clear brand image. The negative impact of brand extension would cause a great damage to parent brand and brand family. From a manager and marketer’s perspective, an operation of branding should maintain brand messages and associations within a consistency and continuum in the long way. Because the effects of negative impact from brand extension are tremendous and permanently. Every messages or brand extension can dilute the brand in nature. Brand extension or brand stretching is a marketing strategy in which a firm marketing a product with a welldeveloped image uses the same brand name in a different product category. The new product is called a spinoff. Organizations use this strategy to increase and leverage brand equity (definition: the worth and longterm sustainability just from the renowned name). An example of a brand extension is Jellogelatin creating Jello pudding pops. It increases awareness of the brand name and increases profitability from offerings in more than one product category. A brand39。s associations are to the brand39。s extension is one of the new product development strategies which can reduce financial risk by using the parent brand name to enhance consumers39。 extension of productrelated association and nonproduct related form of brand extension, is a licensed brand extension. Where the brandowner partners (sometimes with a petitor) who takes on the responsibility of manufacturer and sales of the new products, paying a royalty every time a product is sold. Categorisation theory Researchers tend to use “categorisation theory” as their fundamental theory to explore the links about the brand extension. When consumers face thousands of products, they not