Disclosed is a flexible surgical instrument system, comprising a flexible surgical instrument (10). The flexible surgical instrument (10) comprises a flexible continuous body structure composed of a distal structural body (11), a proximal structural body (16) and a middle connecting body (15). The distal structural body (11) comprises a distal structural segment (12, 13), the distal structural segment (12, 13) comprising a distal spacing disk (121, 131), a distal fixing disk (122, 132) and structural backbones (123, 133). The proximal structural body (16) comprises a proximal structural segment (17, 18), the proximal structural segment (17, 18) comprising a proximal spacing disk (171, 181), a proximal fixing disk (172, 182) and structural backbones (173, 183). The middle connecting body (15) comprises channel fixing plates (152) and a structural backbone guide channel (151). A driving unit fixing plate (21) is arranged behind the channel fixing plates (152), a plurality of cable transmission mechanisms (22) for converting a rotational motion input into a linear motion output are arranged between the driving unit fixing plate (21) and the channel fixing plate (152), an output end of each of the cable transmission mechanisms (22) is connected to one end of a driving backbone (211) via a linear motion mechanism, and the other end of the driving backbone (211) passes through the proximal spacing disk (171, 181) and is then securely connected to the proximal fixing disk (172, 182).