Fruit quality characteristics are an important issue for mandarins, which is the second plant species following orange, which is the most produced and consumed among citrus fruits. In order to develop new mandarin varieties, it is necessary to understand the genetic reasons underlying these traits. In this study, we try to understand the genetic basis of these features with QTL mapping. As a result of the mapping, 7 QTLs were identified among 32 phenotypic features. These are QTLs related to fruit acidity, fruit skin thickness, and seed number.