A flexible surgical instrument system(10, 10a), comprising a flexible continuum structure comprising a distal structure (11, 11a), a middle connecting body (15, 15a) and a proximal structure (16, 16a) linked in sequence, with a proximal end of the distal structure (11, 11a) being linked to the proximal structure (16, 16a) via the middle connecting body (15, 15a), and a distal end thereof being a surgical effecting end; the distal structure (11, 11a) comprising at least one distal segment (12, 12a, 13, 13a) each comprising a distal fixation disk (122, 122a, 132, 132a) and a structural backbone (123, 123a, 133, 133a); and the proximal structure (16, 16a) comprising at least one proximal segment (17, 17a, 18, 18a) each comprising a proximal fixation disk (172, 172a, 182, 182a) and a structural backbone (173, 173a, 183, 183a), the flexible surgical instrument system (10, 10a) further comprises a transmission driving unit (21, 21a) linked to the proximal structure (16, 16a); and; characterized in that, the transmission driving unit (21, 21a) comprises at least one transmission mechanism (22, 22a) driving the proximal segment (17, 17a, 18, 18a), the transmission mechanism can convert a pair of rotary motion inputs with axes parallel to each other into: a first rotary motion output with a first axis perpendicular to the axes of the rotary motion inputs and used for controlling a bending angle of a bending plane of the proximal segment (17, 17a, 18, 18a), and a second rotary motion output with a second axis parallel to the axes of the rotary motion inputs and used for controlling the direction of the bending plane, and the second axis extends along a length of the proximal segment (17, 17a, 18, 18a) at zero-degree bending angle; so as to drive the proximal segment (17, 17a, 18, 18a) to bend or turn in any arbitrary direction, and to further drive the distal segment (12, 12a, 13, 13a) linked thereto to bend or turn in the opposite direction. the flexible surgical instrument system (10, 10a) further comprises a transmission driving unit (21, 21a) linked to the proximal structure (16, 16a); and; characterized in that, the transmission driving unit (21, 21a) comprises at least one transmission mechanism (22, 22a) driving the proximal segment (17, 17a, 18, 18a), the transmission mechanism can convert a pair of rotary motion inputs with axes parallel to each other into: a first rotary motion output with a first axis perpendicular to the axes of the rotary motion inputs and used for controlling a bending angle of a bending plane of the proximal segment (17, 17a, 18, 18a), and a second rotary motion output with a second axis parallel to the axes of the rotary motion inputs and used for controlling the direction of the bending plane, and the second axis extends along a length of the proximal segment (17, 17a, 18, 18a) at zero-degree bending angle; a first rotary motion output with a first axis perpendicular to the axes of the rotary motion inputs and used for controlling a bending angle of a bending plane of the proximal segment (17, 17a, 18, 18a), and a second rotary motion output with a second axis parallel to the axes of the rotary motion inputs and used for controlling the direction of the bending plane, and the second axis extends along a length of the proximal segment (17, 17a, 18, 18a) at zero-degree bending angle; so as to drive the proximal segment (17, 17a, 18, 18a) to bend or turn in any arbitrary direction, and to further drive the distal segment (12, 12a, 13, 13a) linked thereto to bend or turn in the opposite direction.