Oxygen saturation (SO2) for clinical observation of the disease changes provides a meaningful indicator. Traditional oxygen saturation analyses adopt the dual-wavelength and multi-wavelength photoplethysmography to achieve non-invasive detection to reduce the pain of patients. In this paper, a novel approach combining single wavelength laser optical absorption induced photoacoustic and optical scattering, was developed to noninvasively measure blood oxygen saturation, the concentration of deoxygenated haemoglobin (HbR) and oxyhemoglobin (HbO2). A theoretical derivation between the absorption and scattering light characteristics and linear relationship of photoacoustic spectroscopy built the single-wavelength oxygen saturation detection technology, so parameters analysis and imaging of tissue could also be obtained. Here, the phantom experiment successfully demonstrated the quantization of the concentration of a dual-ink combined with green-red ink imitating a blood with hemoglobin and oxygenated hemoglobin. The proportion of red ink, that is to say, pseudo-SO2 was measured with experimental errorless than 6.97%. Then the pseudo-SO2 was imaged in the single tube cross-section for blood vessel copy. Unlike conventional multi-wavelength photoacoustic or near infrared spectroscopy approaches, the proposed single-wavelength method significantly lowers the cost of laser system and portable implementations.