A catalyst composition comprising: a monodentate phosphite ligand represented by the following Formula 1; a monodentate phosphine ligand represented by the following Formula 2; and a transition metal catalyst represented by the following Formula 3, wherein the total content of the entire ligand including the monodentate phosphite ligand and the monodentate phosphine ligand is 1 to 33 moles, based on 1 mole of the transition metal catalyst, wherein R 1, R 2, R 3, R' 1, R' 2 and R' 3 each independently represent: a substituted or unsubstituted cycloalkyl or cycloalkenyl group having 5 to 20 carbon atoms group; or a substituted or unsubstituted aryl group having 6 to 36 carbon atoms; and when R 1, R 2, R 3, R' 1, R' 2 and R' 3 are substituted by a substituent, the substituent is nitro (-NO 2), fluorine (-F), chlorine (-Cl), bromine (-Br) or an alkyl group having 1 to 20 carbon atoms, [Formula 3] M(L 1) x (L 2) y (L 3) z wherein M is one selected from the group consisting of cobalt (Co), rhodium (Rh), iridium (Ir), ruthenium (Ru), iron (Fe), nickel (Ni), palladium (Pd), platinum (Pt) and osmium (Os), L 1, L 2 and L 3 each independently represent one selected from the group consisting of hydrogen, carbonyl, cyclooctadiene, norbornene, chlorine, triphenylphosphine and acetylacetonato (AcAc), and x, y and z each independently represent 0 to 5, with the proviso that all of x, y and z are not zero,wherein the content of each of the monodentate phosphite ligand and the monodentate phosphine ligand is 0.5 to 32.5 moles, based on 1 mole of the transition metal catalyst,wherein a mix ratio of the monodentate phosphite ligand and the monodentate phosphine ligand is 5:1 to 1:5, based on weight. a monodentate phosphite ligand represented by the following Formula 1; a monodentate phosphine ligand represented by the following Formula 2; and a transition metal catalyst represented by the following Formula 3, wherein the total content of the entire ligand including the monodentate phosphite ligand and the monodentate phosphine ligand is 1 to 33 moles, based on 1 mole of the transition metal catalyst, wherein R 1, R 2, R 3, R' 1, R' 2 and R' 3 each independently represent: a substituted or unsubstituted cycloalkyl or cycloalkenyl group having 5 to 20 carbon atoms group; or a substituted or unsubstituted aryl group having 6 to 36 carbon atoms; and when R 1, R 2, R 3, R' 1, R' 2 and R' 3 are substituted by a substituent, the substituent is nitro (-NO 2), fluorine (-F), chlorine (-Cl), bromine (-Br) or an alkyl group having 1 to 20 carbon atoms, wherein M is one selected from the group consisting of cobalt (Co), rhodium (Rh), iridium (Ir), ruthenium (Ru), iron (Fe), nickel (Ni), palladium (Pd), platinum (Pt) and osmium (Os), L 1, L 2 and L 3 each independently represent one selected from the group consisting of hydrogen, carbonyl, cyclooctadiene, norbornene, chlorine, triphenylphosphine and acetylacetonato (AcAc), and x, y and z each independently represent 0 to 5, with the proviso that all of x, y and z are not zero,wherein the content of each of the monodentate phosphite ligand and the monodentate phosphine ligand is 0.5 to 32.5 moles, based on 1 mole of the transition metal catalyst,wherein a mix ratio of the monodentate phosphite ligand and the monodentate phosphine ligand is 5:1 to 1:5, based on weight.