In response to the challenge of achieving precise spraying in narrow and complex environments, a flexible cable-driven continuous spray gun with multiple degrees of freedom and variable diameter functionality is devised. Initially, the design of the spray gun structure is undertaken, incorporating multi-joint continuous mechanisms and joint diameter adjustment mechanisms. Subsequently, kinematic analyses of the cable-driven spray gun are conducted for single and multiple joints, elucidating the mapping relationships between the drive space, configuration space, and working space of the spray gun. Finally, employing Monte Carlo methods, simulation and comparative analysis are conducted on the working spaces of the spray gun under different diameters. Simulation and analysis results validate that the designed continuous spray gun exhibits a certain degree of freedom and flexible operational space.