Acrylamide-dicyanodiamide macromer (M) is a new cationic condensation polymer of acrylamide (Am), dicyanodiamide (D), formaldehyde (F), and ammonium chloride (NH4Cl) with C=C as one of the end groups. The process of condensation was monitored by high-pressure liquid chromatography, and C=C was identified by H-1 NMR. Investigation on the kinetics of reactions between Am and F as well as D and F supported the suggestion about the polycondensation mechanism. In the synthesis of M, feed composition remarkably affected its molecular weight (($) over bar M(W)) and structure. The higher the ratio of Am/D, the lower ($) over bar M(W), and a fraction of molecular chains contains more than one C=C; conversely, the lower the content of Am, the higher ($) over bar M(W),, and some molecular chains contain no C=C. M can polymerize with Am to produce graft copolymers, which has been confirmed by GPC. Two copolymers were obtained by adjusting the dosage of Am. The charge density, molecular weight, and molecular structure of the copolymers have been characterized, and their viscosity behavior in aqueous solutions has been studied.