This study reports two non-intrusive visualization techniques for planar distribution of scalar fields in microfluidic systems based on spontaneous Raman imaging. For temperature measurements, a two-wavelength Raman imaging technique was proposed using two cameras and optical filters. In the second technique, total internal reflection Raman imaging was utilized for measurements of near-wall ion concentration employing the surface-selective illumination induced by the evanescent wave. Each technique was applied to channel flow following a calibration experiment which provided the relationship between Raman intensity and temperature or concentration. The measurement results demonstrate their potential for quantitative visualization of the scalar quantities with micron-resolution.