The invention provides a horizontal omnidirectional displacement amplification type SMA energy dissipation and seismic mitigation device, and belongs to the technical field of structural vibration control. The device is composed of a top plate, a spherical ring, a gourd-shaped rotating ball body, a high-strength bolt, a lever arm, a hollow circular truncated cone, an SMA stranded wire, a U-shapedlocking ring, a bottom plate, a fastening clamp, a spring bolt and the like. According to the device, through the omnidirectional rotation capacity of the gourd-shaped rotating ball body, the device can still utilize hysteretic deformation of the SMA stranded wire to consume energy under the effect of random and unpredictable multidirectional earthquake, and therefore 360-degree omnidirectional effective damping is provided. Meanwhile, the device amplifies the relative displacement of a pier beam of a bridge structure through a lever spherical hinge rotating mechanism, so that the displacement, speed and other responses of the series energy dissipation material are amplified, and the device can play a good energy dissipation role under the effect of large, medium and small earthquakes. Thedevice is clear in structure and high in applicability, and is a safe and efficient energy dissipation and seismic mitigation device.