To evaluate the characteristics of the graft-host interface after penetrating keratoplasty (PKP) using anterior segment optical coherence tomography (AS-OCT). Forty-nine eyes of 49 patients with three different underlying diseases (corneal scar, 22 eyes; bullous keratopathy, 14 eyes; keratoconus, 13 eyes) who underwent PKP were retrospectively reviewed. AS-OCT was performed in all patients and wound profiles of the graft-host junctions were classified into well-apposed junction, gap, step, and protrusion. The correlations between clinical characteristics and wound profiles from the AS-OCT were analyzed. A total of 392 graft-host junctions from 49 eyes were analyzed. Among them, 155 sections (39.5 %) had well-apposed junctions and 237 sections (60.5 %) had malapposed junctions. The most frequent type of malapposition was protrusion (117 sections, 39.9 %). When categorizing the eyes according to the most frequent alignment type among the 8 cross-sections, the alignment pattern showed significant differences between the preoperative diagnosis groups (P = 0.04). Spherical equivalent (P = 0.04) and keratometric astigmatism (P < 0.01) showed significant differences between the alignment groups. Graft-host thickness disparities showed significant correlations with keratometric astigmatism (r = 0.56, P < 0.01) and degree of graft oversize (r = 0.29, P = 0.04). The alignment pattern of wound interface after PKP differed according to the clinical diagnosis before surgery and was significantly associated with spherical equivalent and keratometric astigmatism.