Objective To explore the relationship between sudden deafness and right-to-left shunt (RLS) by contrast transthoracic echocardiography (cTTE) so as to provide new research direction and powerful theoretical basis for the clinical diagnosis and treatment of sudden deafness.Methods One hundred patients with sudden deafness were selected as the sudden deafness group and 100 healthy subjects as the control group. The incidence of RLS, the size and type of shunt between the sudden deafness group and the control group were compared. The sudden deafness group was subdivided into RLS positive group and RLS negative group by cTTE, and the differences in gender, concomitant symptoms, comorbidities, deafness classification and efficacy between the two subgroups were analyzed.Results There were significant differences in the incidence of RLS, mass flow rate and shunt type between the sudden deafness group and the control group (all P＜0.05). In the sudden deafness group, the patients with positive RLS were younger than those with negative right-to-left shunt (P＜0.05).Conclusion The occurrence of sudden deafness is related to RLS, and the detection rate of RLS can be effectively improved by using cTTE and Valsalva maneuver.