Abstract: For aircraft engine parts, deep machining marks, wear marks, attachments, and uneven coating surface may be considered as suspected cracks in the process of quality inspection. The characteristics of these common suspected cracks are summarized by means of metallographic analysis and other methods. Compared with real cracks, suspected cracks due to deep machining marks and wear marks are usually regularly distributed, blunt at both ends and the bottom of the depth direction of the suspected cracks. The bottom of the suspected cracks can be observed vaguely or even clearly, and they can be removed by surface grinding. The suspected cracks due to attachments are generally wide, sometimes with infiltration tips at both sides. The micro morphology of the suspected cracks due to surface coating cracks generally shows the characteristics of crazing. The characteristic information of the suspected cracks can be obtained by means of microscopy, scanning electron microscopy, grinding verification, etc., and the nature of the suspected cracks can be confirmed through comprehensive analysis and judgment based on the processing and application history.