Disclosed is a flexible surgical instrument system (10), comprising a flexible continuous body structure consisting of a distal structural body (11), a middle connecting body (15) and a proximal structural body (16) associated in sequence, and further comprising a transmission driving unit (21) linked to the proximal structural body (16). The transmission driving unit (21) comprises a plurality of transmission mechanisms (22) respectively corresponding to proximal driving structural segments (17, 18). The transmission mechanisms (22) can convert a pair of rotary motion inputs with axes parallel to each other into a pair of rotary motion outputs with axes orthogonal to each other. One of the rotary motion outputs with the axis parallel to the axes of the rotary motion inputs is used for controlling the direction of a turning plane of the proximal structural segments (17, 18), and the other rotary motion output with the axis perpendicular to the axes of the rotary motion inputs is used for controlling the turning angle of the proximal structural segments (17, 18) in the turning plane, so as to drive the proximal structural segments (17, 18) in the proximal structural body (16) to turn in any arbitrary direction, and to further drive distal structural segments (12, 13) in the distal structural body (11) linked thereto to turn in the opposite direction.
