The invention discloses a 10 megawatt grade high power waterjetpropulsor impeller balance test fixture, and belongs to the field of a waterjetpropulsor test fixture. The fixture includes a main shaft, a stopping ring, a cone sleeve, a sleeve and a rotary shaft. Through arrangement of the cone sleeve on the main shaft, an installation hole of an impeller matches an outer wall of the cone sleeve. The cone sleeve and the impeller are fastened so that the impeller is installed on the main shaft. Two ends of the cone sleeve are axially positioned by using a shaft shoulder and the sleeve, and thus the impeller is axially positioned. The cone sleeve is circumferentially positioned through keys, and thus the impeller is circumferentially positioned. Through arrangement of a third flange on the sleeve, the sleeve and one end face of the main shaft are fixed by the third flange. Because a gap may be reserved between the third flange and the one end face of the main shaft, the sleeve can still press an end face of the impeller after impeller to be tested is exchanged, and the impeller is axially positioned.