Abstract: An aminated PAN resin was spun by wet-spinning technology. The influence of amination degree on the hydrophilicity of the PAN resin was characterized by the contact angle method. The effect of coagulation temperature, dimethylsulfoxide concentration in the coagulation bath and aminating degree on cross-sectional morphologies of the nascent filament and void structure were investigated by optical microscopy, SEM and mercury porosimetry. Results show that the cross-section shape gets more and more circular with increasing of aminating degree and coagulation temperature. The total void volume decreases with the aminating degree. Some large voids with diameter ranging from 6mm to 100mm were transformed to small voids below 140nm when the aminating degree was enhanced. The proportion of large voids in the total void volume was decreased with increasing coagulation temperature and dimethylsulfoxide concentration.