Abstract: In this paper mechanical architecture and the working principle of 6-HTRT Parallel Robot are introduced. The algorithm of Inverse Position of the parallel robot considering the constraint conditions and the judgement criterion in the case of multi-answer of Inverse Position are presented. Using the algorithm together with searching in three-dimensional space,we get the method of finding the workspace and the formula of calculating the volume of work space,which is used in simulation of workspace. Study of the influence of kinematics and structural parameter on volume and shape of workspace is also implemented with the above method.