The invention provides a system and a method for oil color detection. The system comprises an optical processing unit and a computing device. The optical processing unit comprises a light source, a first collimating lens, sample slots, a cuvette, a cylinder lens, a grating and a linear array CCD sensor. According to the system and the method, a light path is built on the basis of respective property of the optical elements, the linear array CCD sensor is used for acquiring spectroscopic data and sending the same to the computing device through a USB data line; curve of spectrum of oil to be detected is measured by means of mercury lamp marking; spectral analysis is carried out by a logarithmic method, so that color value of chromatic value of the oil to be detected is computed. Compared with the existing lovibond colorimetry test, the method has the advantage that automatic measurement of oil color is achieved, influence from personal error and environmental factor during the visual measurement is avoided, and measurement precision and measurement speed are increased. By the measurement method of averaging measured results based on multiple measurements, reliability of measurement results is improved.