This study surveys the tension differences between Korean domestic and foreign looms and analyses fabric mechanical properties due to warp and weft tension differences using KES-FB system. Paper is divided by two parts. In this 1st paper, fabric is designed as 5 harness satin weave using 75d/36f warp and 100d/192f weft polyester filaments, and is woven by $Omega^circledR$ rapier loom by Textec Co.Ltd and Picanol$-GTX^circledR$ rapier loom by Picanol Co.Ltd respectively. These grey fabrics are processed on the same dyeing and finishing processes. Weavability is also analysed by measuring warp tension variation according to the warp position, the relationship between shed amount and the warp tension on one fixed heald frame is surveyed, and the relationship between end breaks and warp and weft tensions is also discussed.