There are several reasons why a one-year-old baby’s hair is yellow: First, the child’s hair color and how much it is related to the parents’ genetics, such as the parents’ yellow color, the child’s hair color is likely to be yellow as well. Second, the acquired nutritional factors, such as the presence of iron deficiency anemia, vitamin deficiency and trace element deficiency, the child will also appear yellow hair. Third, some diseases can cause the child’s hair yellow, such as phenylketonuria, the child’s hair will become more and more yellow, but the child’s skin will become more and more white accompanied by intellectual development is not sound. You should pay attention to the reasonable arrangement of diet, correct the habit of partial eating, picky eating, can be appropriate to eat more meat, eggs, milk and all kinds of vegetables, fruits, if necessary, to the hospital to improve the trace elements and other related testing.