The Hanbok has changed over time. It previously had a curved Barae, but has transformed into a straight one that provides a more modern and sophisticated style. The development of the staining technique has resulted in more varied colors and designs that have become more luxurious. I analyzed the Dolbok of the past and present and suggested a Dolbok design that considers functionality, practicality and economy. My design is a fusion Hanbok based on a traditional Hanbok for baby boys and a Dolbok for girls. Contemporary society does not reuse or hand down clothes due to the abundance of resources. This study created some functional and economical methods to adjust the size of Hanboks and allow children to wear them for a longer time. First, I made it possible to adjust the length of the skirt by slip stitching or catch stitching with Seurandan (ornate lower band) and by putting a button on the shoulder part of the skirt for baby girls. The width of the skirt is designed for a 4 year old instead of a 1 year old in order to adjust for children growing up and maintain a stylish look, despite having an overlapped area. Second, I made a baby boy's vest with a belt in a traditional that was not uncomfortable for width variation. Third, I made Geodeulji (sleeve-ends trimmed with wide bias) to enable sleeves to be long or short. The Geodeulji will enhance decorative effect if it is made with a variety of fabric colors. Fourth, I made the width of clothes adjustable by adding a Korum (tie) On-Jeogori for baby boys and girls. There are many study cases on Hanboks but few cases on modern Dolboks. I believe that many designers should continue to study a fusion Hanbok within the framework of a traditional Hanbok to develop a garment that is comfortable to wear.