The invention discloses a method for generating an extreme ultraviolet coherent light source with approximate circular deflection. The method comprises the following steps of (S1) enhancing linear polarization incident laser until the intensity level of the linear polarization incident laser reaches 1013-1014W/CM(2); (S2) performing interaction on the enhanced incident laser and diatomic gas molecules to generate a harmonic; adjusting an included angle between the polarization direction of the linear polarization incident laser and a molecular axis until a harmonic stage required for generation of the light source is acquired; and (S3) converting spectra of two harmonic components of which the energy intensities are equal to each other and the relative phases are 90 degrees in the harmonic stage into two attosecond pulses, and synthesizing the two attosecond pulses to obtain the extreme ultraviolet coherent light source with approximate circular deflection. A harmonic spectrum has two components in two different directions; the energy intensities of the components of the harmonic spectrum in the harmonic stage are equal to each other; and the relative phases are 90 degrees. By the method for generating the extreme ultraviolet coherent light source with approximate circular deflection, the generated extreme ultraviolet coherent light source with approximate circular deflection is high in harmonic efficiency and short in pulse width.