•A new model is proposed to evaluate the thermal performance of airship.•The thermal model of solar array is discretized using finite volume method.•The effect of solar array on thermal performance of airship is unneglectable.•Temperature distribution of airship is affected by the atmospheric model.•Cloud shows negative effects on the temperature of airship for MLS atmosphere. The wasted heat generated by the solar array on stratospheric airship may deteriorate the conversion efficiency and affect the energy system of the airship. Therefore, accurate understanding on the thermal characteristic of solar array is critical important to the design and operation of stratospheric airship. The thermal model of solar array is developed using finite volume method while the envelope and helium are modeled as a multi-node system in this paper. Based on which, a computer code is programmed in FORTRAN. The temperature variation and the three-dimensional distribution of a solar powered stratospheric airship are presented. The effect of solar array on the thermal performances of a stratospheric airship is described. The key factors such as wind velocity, insulation layer and atmospheric model that affect the thermal characteristics of solar powered airship are studied in detail. The results are conducive to understanding the thermal behaviors of solar powered stratospheric airships.