The authors have previously proposed a novel refractive index two-dimensional sensing technique named "parallel scan spectral surface plasmon resonance imaging". In the technique, with a line-shaped light illumination, an image acquired with CCD detector could provide both SPR wavelength information and one-dimensional spatial distribution, and then provide one-dimensional distribution of refractive index with further calculation. Thus, two-dimensional distribution of refractive index of the entire sensing area can be obtained with one-dimensional optical line parallel scan. The technique offers advantages of both high sensitivity and high throughput, and could have potential applications in microarray analysis. In the present paper, the authors improve the data processing methods of the technique. The authors use the refractive index of air as a reference to get over the problem of precision of the incident angle. The authors also sense a manually dotted Legionella pneumophila mip DNA probe array with this technique and prove the feasibility of sensing microarrays by this highly sensitive and label-free technique. The relation between the equivalent refractive indices and the concentrations of the dotted Legionella pneumophila mip DNA probes is obtained, which has important reference value for further study.