An efficient approach for more selective synthesis of higher linear alpha-olefins was achieved by utilizing suitable reaction media in FTS reaction. About 41.4% average alpha-olefins content in C-5-C-25 fractions was obtained at W/Fd((CO+H2)) = 5 g-cat h mol(-1) in n-C-10 solvent, which is markedly higher than the value (2.5%) obtained in 85% N-2 + 15% n-C-6.