High quality liquid fuels for diesel engine are normal paraffins with C-10-C-20. The most promising method to make them from other carbon resources is the Fischer-Tropsch synthesis (F-T) which gives wide range of product distribution. Higher paraffins can be cracked with a conventional method to diesel fraction while lighter ones cannot. The present authors have developed a new F-T process that makes wax products selectively with reduced gaseous products. Efficient transportation of reactants and products to the inside of catalyst bed and pellet, quick heat transfer, and in situ wax extraction from catalyst by supercritical fluid were accomplished. The process is operated under supercritical conditions of light paraffins and in the presence of small amounts of 1-olefins. The added 1-olefins are assumed to be the seed of carbon chain propagation of C-1 monomer to promote the wax formation. (C) 2000 Elsevier Science B.V. All rights reserved.