A knee trial which is coupled to identify the mobility of an implant before the implant is implanted by total knee arthroplasty, and more particularly, a detachable knee trial which includes a plate trial, an insert trial, and an adapter for easy attachment and detachment of the two trials, wherein the adapter includes an elastic member on one side thereof to firmly couple the two trials by pressing the plate trial and the insert trial with opposite ends of the elastic member and to alleviate the burdens of an operator and a patient by allowing the adapter to be attached and detached even only with a simple operation of pressing the adapter and compressing the elastic member by a hand and promptly and precisely performing an operation of selecting an implant of a suitable size while applying various trials in the total knee arthroplasty process and shortening surgery time, alleviating the burdens of a surgeon and a patient, and wherein one side of the adapter is formed of plastic, making it possible to couple the plate trial and the plate implant without leaving a flaw and the like in the plate trial and the plate implant.