The reflexive property of the ear can cause various physical attributes to appear on the auricle in the presence of bodily disorders. The association of auricular signals (presence or absence of discoloration, marks after pressing, tenderness, and electrical resistance) and diabetes mellitus (DM) should be further investigated because auricular diagnosis is an objective, painless, and noninvasive method that provides rapid access to information. A matched case-control study on 282 subjects was conducted. Cases (n = 141) were defined as those diagnosed with type 2 DM (T2DM). Every subject in the case group was matched with the control by age and gender. Ear diagnosis was conducted in three aspects: inspection, electrical detection, and tenderness testing. Results suggest that the tenderness and electrical conductivity of some auricular points, including "pancreas and gallbladder," "endocrine," "kidney," "lower tragus," "heart," and "eyes," were associated with T2DM status in Chinese population. In the subgroup analyses, certain auricular signals were also associated with glycemic control, disease duration, and related complications. Auricular diagnosis could be considered as a screening method for vulnerable populations with T2DM risk. Thus, appropriate interventions can be implemented to prevent or delay the progression of T2DM.