Objective： To compare the technician fabrication time and clinical working time of custom trays fabricated using two different methods, the three-dimensional printing custom trays and the conventional custom trays, and to prove the feasibility of the computer-aided design/computer-aided manufacturing (CAD/CAM) custom trays in clinical use from the perspective of clinical time cost. Methods: Twenty edentulous patients were recruited into this study, which was prospective, single blind, rando-mized self-control clinical trials. Two custom trays were fabricated for each participant. One of the custom trays was fabricated using functional suitable denture (FSD) system through CAD/CAM process, and the other was manually fabricated using conventional methods. Then the final impressions were taken using both the custom trays, followed by utilizing the final impression to fabricate complete dentures respectively. The technician production time of the custom trays and the clinical working time of taking the final impression was recorded. Results: The average time spent on fabricating the three-dimensional printing custom trays using FSD system and fabricating the conventional custom trays manually were (28.6±2.9) min and (31.1±5.7) min, respectively. The average time spent on making the final impression with the three-dimensional printing custom trays using FSD system and the conventional custom trays fabricated manually were (23.4±11.5) min and (25.4±13.0) min, respectively. There was significant diffe-rence in the technician fabrication time and the clinical working time between the three-dimensional printing custom trays using FSD system and the conventional custom trays fabricated manually (P<0.05). Conclusion: The average time spent on fabricating three-dimensional printing custom trays using FSD system and making the final impression with the trays are less than those of the conventional custom trays fabricated manually, which reveals that the FSD three-dimensional printing custom trays is less time-consuming both in the clinical and laboratory process than the conventional custom trays. In addition, when we manufacture custom trays by three-dimensional printing method, there is no need to pour preliminary cast after taking the primary impression, therefore, it can save the impression material and model material. As to completing denture restoration, manufacturing custom trays using FSD system is worth being popularized.