Cotton fiber is a type of natural fibers. Using natural fibers to fabricate textile can not only decrease the consumption of synthetic fibers, but also reduce the environmental pollution. This study aims to fabricate elastic knitted fabrics and evaluate their properties. Polyester (PET) filaments and rubber threads serve as the warp while cotton yarn serves as the weft for warp knitting. A crochet machine makes the warp and weft into warp knits with desirable stretchability, during which the amount (single/double) and the ply number (1-, 2-, and 3-ply) of the weft are further varied. The resulting warp knits are evaluated for water absorption, air permeability, and mechanical properties. As demonstrated by the experimental results, the warp knits with single 1-ply weft (S1) yield an optimal air permeability of 224.6 cm3/cm2/s and stiffness along the warp direction of 4.74cm. The warp knits with single 2-ply weft (S2) display an optimal tearing strength of 86N while the warp knits with double 3-ply weft (D3/3) has an optimal tensile strength of 708N.