In the past, for all kinds of underwear, including children’s, design was not matter if the texture or the material of underwear was good. Because the underwear was not visible. However, due to the improvement of income level and the development of technology, it has become difficult to differentiate by material. In addition, as the consumption trend has changed like underwear outfit, attention on pattern design, visual elements and emotional elements, it has become more important to apply premium pattern on underwear. Overseas leading companies have been aware of such trends quickly and released related products, but most domestic companies have not been releasing related products due to lack of experience, and design and cost problems. This study aims to develop pattern design in children applying emotional lifestyle so that consumers who buy only foreign brand products will be interested in domestic products. Development of children underwear pattern should be different from that of ordinary adults. Children should be able to feel soft, comfortable, and relaxed during activity because children’s skin is weak and they have to wear for a long time. Knit (jersey) was suitable considering all of these conditions. In order to develop a character design that meets the market trend, we developed a textile design based on the concept of children’s favorite animal characters, fruits, flowers, and Christmas. Also, we designed pattern which could excite parents, the actual purchaser. So that, their underwear design choices could be broadened. The developed underwear was designed to be able to be worn as a gown, and the design developed in this study was developed and commercialized as an actual product, helping domestic companies to expand the market share of children's wear. Through this case, we confirmed the possibility that the products developed through emotional design could be sold well and there was a need to improve the competitiveness of domestic children’s underwear companies. Also, in order to solve the situation where Korean companies pay for high-priced characters such as Pooh, Tom and Jerry, we need to develop a emotional pattern design applying characters so that competitiveness of domestic companies could be improved.