Porous polyamide membranes have been commercialized for many years and in nowadays widely used in fine separation processes often manufactured by the immersion precipitation process. This process for the membrane preparation involves precipitation of an incipient casting dope metastable. In this paper the morphology of polyamide 6,6 membranes prepared by phase inversion from ternary system (water/chloridric acid/polyamide 6,6) was investigated. Depending upon the precipitation conditions membranes the morphologics and hydraulic properties that reflect the compartment of membranes. The MP10 and MP15 membranes had been characterized in the FT-IR, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The formation of the dense layer can be observed in the scanning electronic micrographs (SEM). It can be observed that approximately 60% of the distribution of the pores were found in the band between 7 and 6 nm (mesoporous system). It can be concluded that the gotten membrane is mixing, therefore presents a dense part and this membranes was a promising candidate for nanofiltration (NF) and osmosis reversal (OR) process.