The invention relates to a three-dimensional spacer fabric reinforced space membrane material, a preparation method and a processing device thereof. The preparation method includes: in a three-dimensional spacer fabric running process, firstly applying tension along the fabric running direction and maintaining the tension unchanged, making spacer yarns in the fabric at a vertically straight state,then disposing an opening with a length equal to the width of the fabric at the fabric top cloth surface along a direction perpendicular to the fabric running direction, letting the upper layer and lower layer of the fabric staggered horizontally and the spacer yarns at an inclined tense state, and finally compounding the composite fabric with a membrane material to obtain the three-dimensional spacer fabric reinforced space membrane material. The processing device includes a cloth feeding roll, a tension roll, a sizing mechanism, a shaping mechanism, a lamination mechanism, a post-treatmentmechanism and a collection mechanism that are arranged in sequence. The final product has a composite layer structure including a plurality of membrane materials layers and a fabric layer between themembrane material layers, and the spacer yarns in the fabric can move freely and have no adhesion. The preparation method provided by the invention is simple in process, the processing device has a simple structure, and the product has excellent mechanical properties.