Hydraulic flexible cable cutting knife

The invention discloses a hydraulic flexible cable cutting knife, which comprises a control valve, a seawater or fresh water hydraulic cylinder and a shear movement mechanism which are connected in order, wherein the control valve controls the hydraulic cylinder to extend and retract; the hydraulic cylinder drives the shear movement mechanism to open and close by extending and retracting so as torealize shearing; the shear movement mechanism adopts a connecting rod-slide block mechanism; a slide block guide rail is integrated with the cylinder body into a whole, which has the characteristicsof compact structure and high rigidity; a reversing valve is designed to have a three-position four-way structure; a contact mode of a valve plug and a valve seat of the reversing valve adopts a floating structure; and under the action of spring pressure, the valve plug and the valve seat always contact reliably, and a clearance after abrasion can be automatically compensated so as to greatly improve the reliability and service life of a seal. The hydraulic flexible cable cutting knife takes seawater or fresh water as a working medium, has the characteristics of high efficiency, large operational depth, convenient operation and good environmental compatability, and can be widely used for underwater and land shearing operation.