A novel wet strength agent PAEP was prepared through chemical modification of polyamide-polyamine epichlorohydrin (PAE) resin with polyvinyl alcohol (PVA). PAEP/organoboron composite wet strength agent was also introduced in the papermaking process to increase the crosslinking among fibers. The corresponding structure and properties were characterized by IR, SEM, Zeta potential analysis and TG. The adsorption behavior of PAEP in fiber was investigated, as well as the effects of PAE, PAEP and PAEP-organoboron dosage on the wet strength of paper. It was found that the adsorption amount of PAEP in fiber increased from 2.3 mg/g to 8.1 mg/g with the increase of PAEP dosage from 2.5 mg/g to 30 mg/g, whereas the adsorption efficiency decreased from 81.8% to 21.12%. In comparison with PAE, the thermal degradation residue of papers treated with PAEP and PAEP-organoboron increased by 122.67% and 269.60%, respectively. The dry, wet tensile index increased by 22.5% and 101.41% when the organoboron content in PAEP-organoboron was 50%. And the retention rate of tensile index increased by 69.20%. Compared with cationic polyacrylamide (CPAM) and cationic starch, the PAEP-organoboron wet strength agent was also endowed with better strengthening efficiency.