The dynamic vibration absorber with grounded negative stiffness has good vibration control effect， but in practical engineering， the negative stiffness components are unable to be directly connected to the ground for a variety of applications. Therefore， a type of the dynamic vibration absorber with ungrounded negative stiffness is proposed in this paper. According to the established theoretical model， the frequency response function of the system is obtained， and the maximum value minimization theory is used to get the optimal design parameters of the dynamic vibration absorber with ungrounded negative stiffness， which is compared with other existing dynamic vibration absorber models. The calculation results show that due to the introduction of negative stiffness components， the vibration control effect of the dynamic vibration absorber with ungrounded negative stiffness is significantly better than that of traditional linear dynamic vibration absorber. The related research provides a theoretical reference for the engineering application of dynamic vibration absorber with negative stiffness.