There are many bad habits that can cause children’s malocclusion, parents, kindergarten and school teachers should have an understanding of them, which is important for the prevention of children’s malocclusion. 1, finger sucking habits: lead to open jaw deformity and arch narrowing, palate cover high arch, upper front teeth protruding, open lips and teeth and far in the wrong jaw and other deformities, fingers can also appear callus and finger bending. 2, bad tongue habits: can form the front teeth part of the open jaw; lick tongue habits can make the front teeth to the lip side tilt, and gap; tongue habits easily caused by the front teeth open jaw and jaw protrusion deformity. 3, bad biting lower lip habits: can cause upper front teeth lip to tilt and interdental gap, lower front teeth tongue side tilt and crowded, facial manifestations of open lips and teeth, upper front teeth protruding and lower front teeth shrinkage, etc.; and biting the upper lip habits are prone to the formation of mandibular protrusion, anterior anti-mandibular (Baotian) and other deformities. 4. Biting habit: small open jaws can be formed in specific parts of the dental arch. 5, open-mouth breathing habits: can cause the upper arch narrow, palate cover high arch, maxillary teeth protruding or crowded teeth, and even lead to open lips and teeth, gums hypertrophy and hyperplasia, bleeding gums. Experts remind: early correction of children’s oral bad habits, can play an effective preventive role in malocclusion.