Abstract: An eco-friendly polymeric additive, sodium alginate (SA) developed as functional additives with polyamideamine-epichlorohydrin (PAE) was used to improve the mechanical properties of wastepaper. The effects of PAE and the binary system of SA-PAE on the regenerative wastepaper properties were investigated. It was found that the PAE-SA binary system had a significant effect on the regenerative wastepaper fiber, and it was obviously better than PAE, which could reduce the dosage of PAE and play a role in environmental protection. Therefore, through the infrared spectrum of PAE, SA, PAE-SA film, the micro morphology of SEM and AFM, the analysis of C and N contents and the determination on the retention rate of fines, the enhancement mechanism of the PAE-SA binary system was studied. The results showed that: when the addition of PAE was 0.8%, the enhancement effect of wastepaper was best. The dry tensile index increased by 17.11% and the wet tensile index increased by 1 500.00% compared with the blank. In the binary system of PAE-SA, when the addition of PAE was 0.8% and the addition of SA was 0.4%, the dry tensile index and wet tensile index increased by 26.65% and 81.25%, respectively.What is more, the burst index and tear index of the wastepaper were significantly enhanced. Through researching the mechanism, it was found that PAE and SA were not involved in the reaction. So the increase of mechanical performance of wastepaper was mainly depend on the electrostatic adsorption and film coating structure by the increase of PAE adsorption, the crosslinking of PAE and itself or fiber, the adsorption of fines between the fibers and the fiber bonding area.