Objective To explore the characteristics of alexithymia and interoception in patients with panic disorder(PD) and its relationship. Methods Thirty-seven patients with PD and 45 healthy controls who met the diagnostic criteria of DSM-Ⅳ were selected.Toronto Alexithymia Scale (TAS) and state-trait anxiety inventory (STAI) were used to assess the characteristics of alexithymia and anxiety symptoms respectively.The heartbeat perception levels were tested by the Mental Tracking Paradigm. Results The detection rate of alexithymia in patients with panic disorder was 37.83%(14/37), but the rate in the normal control group was only 4.44%(2/45), and the difference was statistically significant (χ2=14.42, P<0.05). The total score of TAS (55.11±10.99), factor Ⅰ (20.62±6.78) and factor Ⅱ (14.68±3.70) in the PD group were higher than those in the control group (42.93±9.25, 12.82±4.99, 11.42±3.04; F=20.72, 31.08, 15.31, P<0.01). The levels of the heartbeat perception were higher in the PD group than that in the control group (0.75±0.15, 0.58±0.19; t=4.13, P<0.05). In PD group, the score of STAI were positively correlated with TAS total score and factor Ⅰ and Ⅱ scores(r=0.57, 0.61, 0.47; r=0.54, 0.62, 0.39, P<0.05). There was no significant correlation between the scores of STAI and the level of interoception.The mediating effect of interoception level on alexithymia and state anxiety was not significant while the mediating effect on alexithymia and trait anxiety was also not significant. Conclusions The alexithymia detection rate and interoception sensitivity in patients with panic disorder were higher than those of healthy people.There may be interaction between alexithymia and anxiety symptoms.Interoception may be a clinical feature of panic disorder. Key words: Panic disorder; Alexithymia; Interoception; Heartbeat perception