A fan assembly for a robot vacuum cleaner, comprising an electric motor, a stator impeller, a rotor impeller and a fan cover; the stator impeller having a shaft hole, the electric motor being mounted on one side of the stator impeller, and an output shaft of the electric motor passing through the shaft hole; the fan cover being mounted on another side of the stator impeller, and an end surface of the fan cover away from the stator impeller being provided with an air inlet; the rotor impeller being mounted on the output shaft of the electric motor and located between the fan cover and the stator impeller, wherein the stator impeller comprises a front impeller disc, a rear impeller disc, and a plurality of blades; the front impeller disc comprises a round plate and a ring rim, the ring rim is disposed around a circumferential edge of the round plate and extends towards the electric motor, and the shaft hole is located in a center of the round plate; the rear impeller disc comprises a bottom plate and a first protruding rim, a middle of the bottom plate is provided with a first round hole, the first protruding rim is disposed on the bottom plate around a circumferential edge of the first round hole and extends towards the fan cover; and the plurality of blades are fixed between the ring rim and the first protruding rim and spaced from one another, and gaps between the blades form a plurality of air-guiding passages, the fan assembly further comprising a support seat and a second fastener, the stator impeller being mounted on the support seat; the support seat comprising a base plate and a first leg, a middle of the base plate being provided with a second round hole; characterized in that the base plate is provided with the first leg at two ends of the second round hole along a radial direction of the second round hole respectively; the rear impeller disc further comprises a second leg provided at two ends of the first round hole along a radial direction of the first round hole respectively, the second fastener passing through the first leg and the second leg to fasten the stator impeller to the support seat; and the first leg is provided with a bump, the second leg is provided with a recess matching the bump, and the bump extends into the recess. the front impeller disc comprises a round plate and a ring rim, the ring rim is disposed around a circumferential edge of the round plate and extends towards the electric motor, and the shaft hole is located in a center of the round plate; the rear impeller disc comprises a bottom plate and a first protruding rim, a middle of the bottom plate is provided with a first round hole, the first protruding rim is disposed on the bottom plate around a circumferential edge of the first round hole and extends towards the fan cover; and the plurality of blades are fixed between the ring rim and the first protruding rim and spaced from one another, and gaps between the blades form a plurality of air-guiding passages, the fan assembly further comprising a support seat and a second fastener, the stator impeller being mounted on the support seat; the support seat comprising a base plate and a first leg, a middle of the base plate being provided with a second round hole; characterized in that the base plate is provided with the first leg at two ends of the second round hole along a radial direction of the second round hole respectively; the rear impeller disc further comprises a second leg provided at two ends of the first round hole along a radial direction of the first round hole respectively, the second fastener passing through the first leg and the second leg to fasten the stator impeller to the support seat; and the first leg is provided with a bump, the second leg is provided with a recess matching the bump, and the bump extends into the recess.