Abstract: Modification performance of Hypercoal (HPC) extracted from brown coal as an additive on the structure of carbonization products through co-carbonization with two different coals was examined. The dimension and texture changes of products were observed using polarization microscope and scanning electron microscope. The results show that the pore structure of carbonization products from caking coal is improved by adding additive with larger size, however smaller particles and more additive amount are favorable for weakly caking coal. As a good candidate of binding substance with high thermoplasticity, HPC particles were found to have a tendency to be well dispersed and further excellent adhesion between coal particles. Excessive expansion of product from caking coal can be inhibited in appropriate conditions. The number and diameter of pore are reduced and pore walls are thickened by adding HPC. Fluidity and fusibility of weakly caking coal are accelerated by the colloid in additive, which would lead to mechanical properties of products improved. Moreover, more factors affecting the product structure via single-carbonization and co-carbonization were taken into account, including moisture in coal and molding pressure of artifact. Special pore structure is formed in the products owing to moisture, and the influence of molding pressure on products is different with coal properties.