The invention relates to an elastic fiber fabric, in particular to an elastic fiber fabric and a preparation method thereof. Warps and wefts are respectively 150D or75D PTS elastic yarns. The elastic fiber fabric is prepared through the steps of winding, twisting, sectional warping, healding, weaving, blank inspection, unrolling and flattening, pre-shrinking treatment, presetting, dyeing, reduction clearing and finishing. The elastic fiber fabric and a preparation method thereof have the advantages as follows: the structure is simple, the chemical fiber differentiation is promoted, the added value is increased, the preparation steps are scientific and reasonable and conform to the basic state policy of energy conservation and emission reduction, and the fabric feels like nylon, has a bright and pure color, is far lower than spandex in price and is a preferred garment material.