A novel type of optical testing target indoor can be used to simulate the outfield target with complex trajectory, profited from the linear motion system in the structural components. But, the problem of the large span and low stiffness linear motion system of novel optical testing target reduced the testing accuracy of the novel optical testing target. So, firstly, based on the Euler-Bernoulli beam theory, a solution to strengthen the structure in a limited space was proposed. Then, combined with the dynamic characteristics of the linear module structure, the layout of the strengthened beam and the reinforcing plate around it was arranged and the dimensions of the strengthening components were determined by an integrated optimization technique. Finally, modal analysis and vibration test for linear motion system after the installation of the department were implemented. Results show that the first order natural frequency and the second order natural frequency of integral structure of linear motion system are 36 and 55 Hz respectively, and the experimental data are in good agreement with the simulation design date that are 32 and 54 Hz respectively and increases by 1.86 time comparing with the initial structure that first order natural frequency is 14 Hz. These results verify the rationality and reliability of the design of reinforced assembly, at the same time, the structural performance of the strengthened linear motion system meets the requirements of the novel photoelectric testing target, such as light weight, high rigidity, strong anti-interference ability and so on.