Objective To explore the application of multi-slice spiral CT (MSCT) and echocardiogram in patients with suspected aortic dissection (AD) in emergency department. Methods MSCT and transthoracic echocardiography (TTE) were used to examine and diagnose 94 patients with suspected AD, and then the results were compared with enhanced CT angiography (CTA) or surgical results, and the diagnostic accuracy of the two and the detection rates of disease-related damage were analyzed. The detection results of MSCT and CTA on the true or false lumen diameter of AD patients were compared, and then the application value of TTE and MSCT was analyzed in AD patients in emergency department. Results The sensitivities of TTE and MSCT in the detection of AD were 76.31% and 92.11% respectively, and the specificity were 94.44% and 88.88%, and the detection rate of Debakey I by MDCT was higher than that by TTE (P<0.05), and the detection rates of Debakey II and III were higher than those by TTE (P>0.05). The detection rates of intimal flap, thrombus and pericardial effusion by MSCT were higher than those by TTE, and the detection rate of aortic valve disease was lower than that by TTE (P<0.05). There was no significant difference in the true or false lumen diameter between MSCT and CTA (P>0.05). Conclusion Both TTE and MSCT are safe and effective methods for emergency examination of AD patients, and TTE has slightly low diagnostic accuracy, but its operation is more simple and convenient, and it can provide reference information of cardiac function and blood flow status. MSCT has strong image processing capability at the later stage, can conform more detailed information and can provide reference for the surgical regimens, equipment selection and patients prognosis.