This paper comprehensively investigates the buckling load and the stability of a planar linear array deployable structure composed of scissor-like element (SLE) under compression.At present,the researches on deployable structure are mainly focused on configuration design and dynamics characteristics of the mechanisms,but less on structural instability.In fact,when the external load exceeds the structural critical load value,the deployable structure will be permanently deformed or even collapse directly and no longer have any bearing capacity.To address this issue,a new stability model is derived using linear elastic analysis method and substructure method to evaluate the buckling characteristics of the deployable structure with n SLEs when it is carried out in space,which can accurately obtain the structural instability load and can be used quantitatively to optimize the structure for making it have the most stable configuration.In addition,the effects of the number of elements,the length,material properties and flexibility of the bar,and the deployment degree on the buckling of the scissor deployable structure are investigated,and the results of the theoretical analysis are compared with simulation and analytical results,respectively,confirming that the proposed stability model not only is able to effectively predict the structural instability load but also determine which part of the deployable structure is unstable.It can be concluded that the stability of the deployable structure gradually decreases with the increase of the number of elements or the bar flexibility.In the calculation process,the critical load of each sub-element should be considered,and the minimum value of the critical loads of all subunits can be regarded as the instability load of the whole structure.