The compensation device of pitching and rolling movement is an important part of the deep-sea mining system. At the top, the lifting pipe is hung in the heaving platform of the mining ship, and at the bottom, it is connected with the mining machine via the buffer and the soft pipe. Under the influence of the pitching, rolling, towing movement of the mining ship and the walking of mining machine, the lifting pipe would not stand vertically; with its bottom has much departure. In order to avoid the lifting pipe from bearing great bending stress and strain which would cause damage, moreover, to make the mining system work safely, it is necessary to design a reasonable connection device which could pitch and roll with the lifting pipe. Based on the above aims, this thesis has done some researches on the compensation device of pitching and rolling movement.The main works are as follows:1、According to the work purpose of the compensation device of pitching and rolling movement, the whole design scheme of the connecting device is presented. The structure of the inner and outer frame and the connection scheme of the inner and outer frame were determined.2、Based on the intensity condition, the main structure of the compensation device of pitching and rolling movement, such as the inner and outer frame, the pitching axis and rolling axis, have been designed and calculated.3、Considering the outer frame and rolling axis, the inner frame and pitching axis as subassembly respectively, the finite element model of them have been established, then their mode analysis have been done. Some lower natural frequencies and corresponding mode shapes have been calculated, the results have been analyzed.4、The static structural analysis of the outer frame subassembly and inner frame subassembly have been finished with finite element method. The stress and displacement nephograms of the model in the worst condition have obtained, the results have been analyzed. 5、A test model has been made based on the existing experiment condition. Static strain measurement and finite element calculation were performed on the model. Through the comparison and analysis between the results of the test and the calculation, the validity of the method of modeling and analysis in this paper could be testified.