Objective To evaluate the feasibility and safety of two different types of left atrial appendage occluder with a single disc cylinder or double disc device. Methods Fourteen healthy canines were subjected to left atrial appendage closure (LAAC) with the single disc cylinder or double disc device percutaneously. Closure was evaluated by left atrial angiography. The cause of death was analyzed by gross specimen examination of dogs that had died unexpectedly. The canines were sacrificed post-procedure at 45, 80, 110 days, and 15 months. Endothelialization of the device surface was evaluated by HE staining, immunofluorescence staining of CD31, and DAPI staining. Results Single disc cylinder devices were implanted in six canines, five of which died within 30 min to 8 h post-procedure, and one canine survived until 15 months. A large number of blood clots were formed on the device surface in four canines, and one-fifth of the device surface in the surviving canine was not covered by new tissue. Double disc occluders were implanted successfully in eight canines. The left atrial appendage of seven canines was sealed completely and a small residual shunt was observed in one canine immediately post-procedure. New tissue had covered the sealing disc completely on day 110. HE and immunofluorescence staining confirmed complete intima formation and neovascularization within 4 months. Conclusions The incidence of acute thrombosis and the mortality rate of LAAC with a single disc device were high. LAAC with double disc devices had less device-related complications and neointima formation was completed by 4 months post-procedure.