Nano fiber mat which will be used for artificial skin, filter, scaffold of tissue engineering, etc. is porous and must be manufactured for superior mechanical strength. Electrospinning method which is mainly used as a manufacturing method of nanofiber has weaknesses of low production speed and low mechanical characteristics, so method of Air Jet Spinning that has recently been studied overcome this weakness. Therefore, this study made solution of 5, 10, 14, 18, 22 wt% with Nylon6 and Formic acid and made polymer fiber with nano diameter with method of Air Jet Spinning. And then, effects of solution condition for morphologic shape and average diameter were investigated and chemical combination and mechanical characteristics were examined. As the result, method of Air Jet Spinning made lots of effects on chain structure of Nylon6. Unlike the electrospinning producing quasi-stable form of gamma type, Nylon6 manufactured by method of Air Jet Spinning has a structure of thermodynamically stable alpha form and mechanical characteristics of Nylon6 mat were also improved.