The invention provide a process for producing directly mixed linear alpha-alcohols having 1 to 18 carbon atoms from synthesis gas comprising hydrogen and carbon monoxide, comprising the step of reacting hydrogen and carbon monoxide over a catalyst to produce mixed linear alpha-alcohols having 1 to 18 carbon atoms and hydrocarbons having 1 to 25 carbon atoms through Fischer-Tropsch process in one step in a reactor, wherein: the mole ratio of hydrogen to carbon monoxide is within the range of 1 to 3; the catalyst is an activated carbon supported cobalt based catalyst; the reactor is a fixed bed reactor, a slurry reactor or a fluid reactor; the reaction is carried out under specific conditions.