A vibration-isolating device based on magnetic damping includes a housing and an internal seat. The housing receives a first magnetic member and has a first buffer. The internal seat has a base portion received in the housing and has a raised portion protruding from the housing. The base portion has a second magnetic member positionally opposite to the first magnetic member to generate a damping effect. A second buffer is between the base portion and the housing and aligned with the first buffer. When an object is fixed to the raised portion, the object and the housing jointly hold the first buffer and leave a gap therebetween. The housing and the base portion hold the second buffer therebetween. When the object receives vibration, the first buffer and the second buffer damp the vibration first and the internal seat uses the damping effect to counteract any remaining part of the vibration.