A method for synthesizing monocyclic aromatic compounds and long-chain olefin compounds from a carbon dioxide-rich synthesis gas, which comprises: i) a step of preparing a hydrocarbon by conducting a Fischer-Tropsch (FT) synthesis process in the presence of an iron-based catalyst using a carbon dioxide-rich synthesis gas with a CO2/(CO + CO2) molar ratio controlled within a range from 0.4 to 0.65 as a source material; ii) a step of separating a C1-C15 short-chain hydrocarbon from the hydrocarbon products; and iii) a step of preparing C6-C12 monocyclic aromatic compounds and C6-C18 long-chain olefin compounds by dehydrogenating the C1-C15 short-chain hydrocarbon in the presence of a crystalline aluminosilicatebased catalyst, hydrogen and water, and wherein the step iii) is performed either - under the condition of a reaction temperature of 300 to 350 °C and a reaction pressure of 5 to 20 bar to maximize the selectivity of the monocyclic aromatic compound, or - under the condition of a reaction temperature of 200 to 270 °C and a reaction pressure of 10 to 20 bar or a reaction temperature of 300 to 350 °C and a reaction pressure of 0.5 to 2 bar to maximize the selectivity of the long-chain olefin compound, wherein the carbon dioxide-rich synthesis gas in the step i) has a H2/(2CO + 3CO2) molar ratio of 0.85-1.1, wherein the step i) is performed under the condition of a reaction temperature of 250-350 oC and a reaction pressure of 10-30 bar, wherein the crystalline aluminosilicate-based catalyst in the step iii) has a Si/AI molar ratio of 10-50 and comprises mesopores with a size of 10 nm or smaller and micropores with a size of 1-8 Å, wherein the crystalline aluminosilicate-based catalyst in the step iii) hasa Brønsted acid site/Lewis acid site ratio of 0.1-3.2, wherein, in the step iii), the molar ratio of hydrogen is 0.1-10 and the molar ratio of water is 0.1-1.3 based on the short-chain hydrocarbon. wherein the step iii) is performed either - under the condition of a reaction temperature of 300 to 350 °C and a reaction pressure of 5 to 20 bar to maximize the selectivity of the monocyclic aromatic compound, or - under the condition of a reaction temperature of 200 to 270 °C and a reaction pressure of 10 to 20 bar or a reaction temperature of 300 to 350 °C and a reaction pressure of 0.5 to 2 bar to maximize the selectivity of the long-chain olefin compound, - under the condition of a reaction temperature of 300 to 350 °C and a reaction pressure of 5 to 20 bar to maximize the selectivity of the monocyclic aromatic compound, or - under the condition of a reaction temperature of 200 to 270 °C and a reaction pressure of 10 to 20 bar or a reaction temperature of 300 to 350 °C and a reaction pressure of 0.5 to 2 bar to maximize the selectivity of the long-chain olefin compound, wherein the carbon dioxide-rich synthesis gas in the step i) has a H2/(2CO + 3CO2) molar ratio of 0.85-1.1, wherein the step i) is performed under the condition of a reaction temperature of 250-350 oC and a reaction pressure of 10-30 bar, wherein the crystalline aluminosilicate-based catalyst in the step iii) has a Si/AI molar ratio of 10-50 and comprises mesopores with a size of 10 nm or smaller and micropores with a size of 1-8 Å, wherein the crystalline aluminosilicate-based catalyst in the step iii) hasa Brønsted acid site/Lewis acid site ratio of 0.1-3.2, wherein, in the step iii), the molar ratio of hydrogen is 0.1-10 and the molar ratio of water is 0.1-1.3 based on the short-chain hydrocarbon. <EOS>