Porous nanofiber has a lot of applications in medical, filtration, pharmacy and tissue engineering, hence, its application is so useful. One method for producing porous nanofiber is electro spinning nano fiber composite and after that extracting nano particles from polymer matrix. In this study, polyamide 6, 6 nanofiber/calcium carbonate composite is produced by electro spinning method. Afterwards, desirable conditions for producing nano fiber were studied. Due to the reaction between formic acid as solvent and calcium carbonate nano particles, the polymer matrix was changed. Subsequently, poly (acrylonitrile) (PAN) was used as solvent and PAN nano fiber was produced with concentration of 14-17 weight percent of PAN and calcium carbonate in di methyl form amide. Thereafter, calcium carbonate nano particles were extracted from poly (acrylonitrile) matrix using diluted chloridric acid bath. Gravimetry, titration and atomic absorption methods were used for measuring the amount of extracted calcium carbonate. The best and most subtle method was atomic absorption. For ascertaining the structure and diameter average, and also for observation of the created porous, TEM and SEM microscopes were used. The SEM pictures show that the nano fiber diameters are between 270-720 nm, and pores diameters are 2-3 of diameter of nanoparticles. Also in figures of TEM, there are pores of one naoparticle or some nanoparticle. The result show that increasing consentration of acid up to 5% , has the maximum of extraction and increasing of concentratio has no effect on it.