Hydraulic dampers are usually used to reduce the vibration of a vehicle, which convert the vibration energy into heat. Except for wasting energy, the unchangeable damping characteristic cannot adapt the various road conditions. Previous work on regenerative damper with changeable damping, which usually consist of one generator have some shortcomings, which consist of energy wasting and small range of damping tuning. Aiming at above problems, a new design principle with multiple-controlled generators is discussed in this paper. Furthermore, a new energy-harvesting damper with multiple-controlled generators (DMCG), which is based on the new design principle is designed. A prototype was built and tested by MTS testing system. The experiment results show that DMCG can not only tune the damping almost linearly, but also extract vibration energy as much as possible.