The invention discloses a non-probability aerothermoelasticity reliability designing method for a hypersonic control surface. The method is characterized in that uncertainties in aerothermoelasticity designing for the hypersonic control surface are considered, and a sample space for uncertain input parameters is established according to a vertex method; the effects of thermal stress generated by aerodynamic heating on inherent attributes of the control surface are considered, and a bidirectional fluid-structure coupling method is achieved to accurately simulate a dynamic response process of the control surface under the effects of gust loads; on such a basis, reliability indexes are introduced, and reliability analysis of a control surface structure is carried out according to upper and lower bounds of analysis results. Based on the steps, with the control surface structure weight as an optimization objective, and with reliabilities of the maximum displacement of the control surface, the maximum root restraint force and the maximum root restraint moment as restraint conditions, non-probability aeroelasticity reliability optimization designing for the hypersonic control surface can be achieved. The method provided by the invention has the advantages that high reliability of the hypersonic control surface structure is ensured while the structure mass is reduced, so that a new thought is provided for the aerothermoelasticity designing for the hypersonic control surface.