A light source module includes a base, a cold cathode fluorescent lamp (CCFL) and an auxiliary light emitting unit. The CCFL disposed on the base provides main light. The auxiliary light emitting unit disposed on the base includes a plurality of light emitting diodes (LEDs) respectively disposed adjacent to two ends of the CCFL. The auxiliary light emitting unit provides auxiliary light to compensate for the main light, wherein the light source module emits scanning light, which is substantially uniformly distributed along a length of the CCFL.