Minimally invasive interventions become popular surgical approaches due to the significant advantages including cosmetic appearance, less blood loss and shorten hospital stay. Robotic assisted minimally invasive surgeries have benefited not only patient on improved surgical performance, but also surgeon on comfortable operation through flexible mechanism. In order to obtain necessary flexibility adopting for different workspace, we developed a new flexible manipulator with a variable curvature bendable joint for surgical intervention. The surgical manipulator consists of an Omni-directional bendable joint, a rigid translational base rod, while their central axes are coincide with each other. The bendable joint is composed of a machined spring, which guarantees a continuous bending motion driven by four tendons with circumferential distribution. The rigid translational base rod is located in the internal channel of the bendable joint, and adjusts the bending curvature of the bending joint by varying the coupling length. The unique design allows the flexible manipulator can quickly adjust the bending curvature of the end effect, which enlarges its surgical application in the workspace of difference volume.