NOVELTY - Method for preparing middle distillate hydrocarbon composition from ethylene involves feeding (a) ethylene into oligomerization reaction zone to form oligomerized product A, separating (b) light/middle/heavy products streams from oligomerized product A, recycling (c) a portion of the light products stream B to the oligomerization reaction zone, and hydrogenating (d) the middle distillate product stream C. At least a portion of hydrogenated middle distillate product stream C is recovered as middle distillate hydrocarbon composition.    USE - Method for preparing middle distillate hydrocarbon composition from ethylene/ethanol used for diesel fuel composition, jet fuel composition (all claimed) heating fuel, lamp oil and static engine fuel for turbine engine.    ADVANTAGE - The method enables effective preparation of middle distillate hydrocarbon composition from ethylene/ethanol having low pour point temperature and cloud point temperature.    DETAILED DESCRIPTION - Method for preparing middle distillate hydrocarbon composition from ethylene involves feeding (a) an ethylene into an oligomerization reaction zone containing catalyst to form an oligomerized product stream A, separating (b) a light products stream B, a middle distillate product stream C and a heavy products stream D from oligomerized product A, recycling (c) a portion of the light products stream B to the oligomerization reaction zone, and hydrogenating (d) the middle distillate product stream C. At least a portion of hydrogenated middle distillate product stream C is recovered as middle distillate hydrocarbon composition. The oligomerization reaction is carried out at 30-300 degrees C under pressure of 10 bar or more. The light product stream B comprises the fraction of oligomerized product A which boils in the 2-8C mono-olefin boiling range and the middle distillate product stream C comprises a fraction of oligomerized product A which boils above the boiling range of the light product stream B. Method for preparing middle distillate hydrocarbon composition from ethanol involves feeding an ethanol composition to a dehydration reactor containing an ethanol dehydration catalyst, separating a stream comprising ethylene from the effluent of the dehydration reactor, subjecting the stream comprising ethylene into a process for removing water and alcohols, and preparing the middle distillate hydrocarbon composition from the ethylene. INDEPENDENT CLAIMS are included for the following:    (1) diesel fuel composition; and    (2) jet fuel composition.