The design project of a diffractive-refractive hybrid acoustic lens based on binary acoustical principle is presented. In photoacoustic imaging, the diffractive-refractive hybrid acoustic lens, comparing with single acoustic lens, has many advantages including real-time imaging, long imaging focal depth, using time-delay to realize tomographic imaging and especially its achromatization merit to increase imaging resolution. It is simulated that point spread function received after point acoustic source with band width passes through the diffractive-refractive hybrid acoustic lens. Compared with that through single acoustic lens, point spread function is greatly improved in the simulated figure and the influence of axial chromatism on imaging quality is partly eliminated.