A new type Mannich base was developed by the reaction of binary copolymer AM/C ₉ synthesized from C ₉ petroleum fractions with acrylamide as raw materials. The effects of reaction time, reaction temperature, pH of solution and ratio of aldehyde were studied. The apparent viscosity of Mannich was characterized by IR spectroscopy and its structure is characterized. Finally, the performance of the product is analyzed. The results show that the optimum reaction conditions were as follows: The reaction time is 4 h, the reaction temperature is 70 ℃, the pH is 9 and the ratio of dimethylamine to formaldehyde was 1.5. The result of infrared spectrum characterization shows that the product has been synthesized. Synthetic Mannich base has higher viscosity, temperature and salt tolerance compared with traditional HPAM.