This paper is a phase report of the study concerning the subject"Throttling Cavitation Venturi". To improve controle accuracy of the throttling engine，the linear throttling cavitation Venturi with a movable，specially shaped part is used. In our work，the shape of the movable part has been verified to be a rotational paraboloid，which has been proved by tests. The technique to design such a Venturi which makes the relationship between the f1ow rate and the moving distance be linear is presented. For the convenience of designing，some relations between parameters are given and Some problems concerned are discussed. This report may be a reference for those who are engaged in the development of variable-thrust liquid propellant rocket engines and liquid Venturi f1owmeters.