The invention discloses an anti-winding device of an unmanned boat propeller thruster. The anti-winding device comprises a rotary shaft; the left end of the rotary shaft and an external power output shaft are connected through a coupling, and four propellers are mounted at the right end of the outer side face of the rotary shaft at equal angles; an annular protrusion is arranged on the right sideof the outer side face of the rotary shaft, and protrusion positioning spiral insection is formed on the annular protrusion; a movable cutting pipe sleeves the rotary shaft, and embedded spiral insection is formed on the inner wall of the movable cutting pipe; and part of water suspended solids is blocked by a U-shaped shielding rod and a circular ring, left side cutting knives, arc-shaped knivesand right side cutting knives can move in a left-right reciprocating mode in the radial direction of the rotary shaft so as to cut the wound suspended solids, and power of left-right moving of the movable cutting pipe is only assisted by rotary motion of the rotary shaft. The anti-winding device of the unmanned boat propeller thruster is simple in structure, low in cost and good in clearing effecton the wound suspended solids, and thus normal navigation and production work of an unmanned boat are ensured.