A board card turbo fan, comprising: a rotor housing ; and a fan blade structure arranged around the rotor housing and fixed to a periphery of the rotor housing , and the fan blade structure comprising a plurality of fan blades spaced and extending inward towards a central axis of the rotor housing , wherein a cross section of the fan blade as seen in a plane that is orthogonal to the central axis of the rotor housing is a circular arc and a length of the arc is 1/8-1/6 of a circumference of a circle in which the arc is located, and wherein a first end of the arc of the fan blade is an air inlet arranged near the rotor housing and a second end of the arc of the fan blade is an air outlet facing away from the air inlet , the board card turbo fan being characterized in that a diameter of a circle in which the arc-shaped cross section of the fan blade is located is 1/10-1/6 of an outer diameter of the fan blade structure , and in that , as seen in a plane that is orthogonal to the axis of the rotor housing, an angle between - a part of a line which is tangential to the arc at the air outlet and which starts from the air outlet and extends away from the axis of the rotor housing , and - a part of a line which is tangential to the fan blade structure at the air outlet and which starts from the air outlet and extends in a rotation direction of the turbo fan, is an acute angle, so that the axis of the fan blade is close to the axis of the rotor housing , and this acute angle has a magnitude of 45 degrees. a rotor housing ; and a fan blade structure arranged around the rotor housing and fixed to a periphery of the rotor housing , and the fan blade structure comprising a plurality of fan blades spaced and extending inward towards a central axis of the rotor housing , wherein a cross section of the fan blade as seen in a plane that is orthogonal to the central axis of the rotor housing is a circular arc and a length of the arc is 1/8-1/6 of a circumference of a circle in which the arc is located, and wherein a first end of the arc of the fan blade is an air inlet arranged near the rotor housing and a second end of the arc of the fan blade is an air outlet facing away from the air inlet , the board card turbo fan being characterized in that a diameter of a circle in which the arc-shaped cross section of the fan blade is located is 1/10-1/6 of an outer diameter of the fan blade structure , and in that , as seen in a plane that is orthogonal to the axis of the rotor housing, an angle between - a part of a line which is tangential to the arc at the air outlet and which starts from the air outlet and extends away from the axis of the rotor housing , and - a part of a line which is tangential to the fan blade structure at the air outlet and which starts from the air outlet and extends in a rotation direction of the turbo fan, is an acute angle, so that the axis of the fan blade is close to the axis of the rotor housing , and this acute angle has a magnitude of 45 degrees. - a part of a line which is tangential to the arc at the air outlet and which starts from the air outlet and extends away from the axis of the rotor housing , and - a part of a line which is tangential to the fan blade structure at the air outlet and which starts from the air outlet and extends in a rotation direction of the turbo fan, <EOS>