This paper presents a numerical pre-test that considers finite element modelling and optimal sensor placement study for a singular spatial truss structure field vibration test. The singularity and importance of such structure require easier, quicker and cheaper monitoring methods. Vibration-based health monitoring methods determine the modal characteristics of the structure via a limited number of sensors. These characteristics are intrinsic properties, so that a variation in them may be induced by structural damage. Only a limited number of degrees-of-freedom can be measured for the system identification process. By developing a finite element model for the spatial truss structure, these degrees-of-freedom can be identified. Based on these results, Effective Independence Method (EFI) method is employed to determine the optimal sensor number and locations. This methodology is formulated with the use of the modal properties of the structure, where the independence of the target modal shape matrix is maximised in an iterative process, and those degrees-of-freedom that do not contribute to the independence of the target modes are eliminated. It is concluded that utilising just a few number of sensors the result of placement location is improved for structural health monitoring purposes.