Aiming at solving the problems of low flexibility, poor internal extension, and chopstick effect in most laparoscopic surgical robots, this letter presents a flexible tendon-driven continuum surgical manipulator with eight degrees of freedom, called FIORA. The manipulator is composed of three independent flexible segments in series, and each flexible segment includes 12 spherical joints made of aluminum alloy backbone. The manipulator is driven by twelve tendons and has good flexibility and rigidity. The compact actuation unit can meet the requirements of force and position control for each tendon,and provide two degrees of freedom for the manipulator to move forward and rotate. Considering the shape-position relationship of the continuum, a kinematic modeling method based on piecewise constant curvature model is proposed, which can solve the problems of accurate modeling and fast decoupling. Analyzing and comparing similar researches, the manipulator shows excellent working range and flexibility. Experiments verified the accuracy of the kinematics model and the good operating performance of the manipulator.