Aiming at reducing multi-dimensional vibration experienced by vehicle-mounted precise instrument， a multi-dimensional passive vibration isolator is built based on parallel mechanism with joint clearance. The 4-PUU parallel mechanism with axes 45° offset value， which exhibits three translations and one rotation characteristics is synthesized by GF set type synthesis theory. The springs and viscous dampers are added on the active joints， meanwhile the kinematics and dynamics of the multi-dimensional vibra? tion isolator are established. The vibration isolation capability with different values of joint clearance under harmonic and road ran? dom excitations is addressed. The results demonstrate that the proposed multi-dimensional isolator with joint clearance can inhibit multi-dimensional vibration in time and frequency domain significantly. As the value of joint clearance increasing， the vibration iso? lation capability degenerates， especially in x direction. Meanwhile， the first order resonance peak is sensitive to joint clearance， which shifts to low frequency range.