The invention discloses a high-viscosity extrusion forming agent, comprising the following ingredients: 15-20 wt% of rosin modified resin, 10-15 wt% of paraffin No.58, 20-25 wt% of paraffin No.43, 25-30 wt% of paraffin oil, 5-10 wt% of dibutyl phthalate (DBP), 1-5 wt% of coconut amine, and 5-10 wt% of oleamide. According to the invention, extrusion billets can be prevented from cracking in the quick drying process, the extruded billets can be guaranteed to have good shape retention, and the qualified rate of the products is raised.