Normal teeth are arranged in a single curved row. Double row of teeth is a common term for misalignment of teeth, which is manifested by the presence of two teeth side by side on the inner and outer sides of the alveolar bone. Upper and lower anterior teeth are more common, and a few can also occur in the posterior region. It is common in the following situations: 1) permanent teeth have erupted, but the corresponding milk teeth have not yet been lost; 2) permanent teeth are severely misaligned, forming a double row of teeth. Children during the tooth replacement period should avoid too fine food and allow the milk teeth to get proper exercise to ensure the smooth replacement of milk and permanent teeth. For double rows of teeth caused by unerupted milk teeth, it may lead to ectopic eruption of permanent teeth and misalignment, which is generally simpler to deal with, i.e., extraction of unerupted milk teeth is sufficient; for double rows of teeth caused by ectopia of permanent teeth, the patient needs to undergo orthodontic treatment in order to correct it.