Trinidad lake asphalt (TLA) is regarded as a high quality paving asphalt modifier for better road performance and has been used in many countries. However, the high price limits its application to only heavy load surfaces. A co-processing process of fluidized catalytic cracking slurry with coal was developed to produce heavy product (named CS) with asphalt modification ability similar to that of TLA. As a typical example, CS-modified asphalt with CS to base asphalt ratio of 20/80 meets the specifications of ASTM D5710 and BS 3690 for TLA-modified asphalt. The properties of CS-modified asphalt concrete are similar to that of TLA-modified asphalt concrete and satisfy the specifications of JTJ 036-98. Depended on the co-processing conditions used, the yields of the modifier are in the range of 65-80%, with softening point of 90180 degreesC and penetration value of 0-8 (1/10 mm) at 25 degreesC. Asphaltenes content in CS is about 20-70 wt.%, preasphalterles about 5-30 wt.%, and organic residues bout 5-60 wt.%. Hydrogen content and hydrogen distribution of CS vary with the co-processing conditions. The atomic ratio of H/C of CS is lower than that of TLA. (C) 2004 Elsevier B.V. All rights reserved.