Abstract: This study was designed to explore wear characteristics and to predict the wear degree of biomass ring plunger molding machine. Fractal theory and wear mechanism were applied to establish model predicting ring mold die wear. Model-based die wear prediction and analysis were verified experimentally. The results showed that the main wear part of ring mold took place at the inner die wall of the latest designed ring mold plunger. Critical asperity contact surface area ac was dependent on the surface topography and material properties. We validated the established die wear prediction equation taking into account the material and the physical characteristics of the ring mold, and examined the relationship between the average wear rate and several typical parameters. The average wear rate increased with the increase of fractal parameters, molding pressure and equivalent forming speed. Among the two typical ring mold materials and two typical biomass materials, 42CrMo/straw had the lowest average wear rate while 45 steel/wood had the highest average wear rate.