Tensairity is a new kind of hybrid structure system using pre-stress to build the initial stiffness. To study the mechanical performance effected by structural deformation under the initial pre-stress, the form finding analysis of a 60 m span spindle Tensairity was conducted by the improved inverse iteration. The effects of form finding were discussed, and the mechanical performance and economics were compared with truss and beam string structure. The results show that: under the initial state the deformation tolerance could be reduced to 0.67% and the inner force distribution differs obviously, and under the load state the vertical bearing capacity decreases 22.24%. Compared with truss and beam string structure, the stiffness is weaker while the steel consumption is 34.80% less. Form finding analysis could effectively control the deformation tolerance under the initial state though having great impact on the mechanical performance, which holds remarkable economic efficiency and application properties.