The invention discloses a fiber arrangement ultrasonic control device and method in selective laser sintering. The device comprises an ultrasonic wave generator, a transducer, a vibration transmissionrod, an amplitude transformer and a vibration head, wherein the ultrasonic wave generator is connected with the transducer through a cable, the transducer is connected with one end of the vibration transmission rod, the other end of the vibration transmission rod is connected with the amplitude transformer, and the amplitude transformer is tightly connected with the vibration head penetrating allsides of a shaped cylinder and the bottom of a shaped substrate through bolts. The method comprises the steps of spreading powder and then applying ultrasonic vibration to a fiber compound powder layer in the shaped cylinder for a certain time period, then turning off an ultrasonic vibration device and sintering the powder layer, and repeating the steps till sintering is finished. The method is practical and simple, can control orientation and arrangement of fiber in the fiber compound powder material, thereby solving an anisotropy problem of mechanical performance of a sintered piece causedby fiber distribution, and improving the quality of sintered pieces.