Abstract: How to measure the initial elastic lateral stiffness accurately is the first problem of pseudo dynamic testing for researching seismic performance of shearing MDOF (Multiple Degree of Freedom Systems) structure. Multi-Servo-hydraulic control systems of shearing MDOF pseudo dynamic testing have the phenomena of coupling, leading to difficulties in obtaining true lateral stiffness. A new method of measuring story lateral stiffness (Simple-Servo-hydraulic measure method) is presented in this paper. An example is used to demonstrate that the result of the new method is steady. The analysis results showed the testing results are comparable with the calculate results. The analyses illustrates the accuracy of the proposed method.