A vehicle tailight includes a housing seat and a light cover cooperatively defining an accommodation space, and a main light emitting device disposed in the accommodation space and including first and second light emitting members capable of emitting first and second color lights, respectively, a reflective plate, an isolation portion corresponding to the second light emitting members, and a light transmitting plate having a light guide portion for transmitting a portion of the first color light rearwardly to the light cover and to guide the other portion thereof to reflect forwardly onto the reflective plate, which in turn, reflects the first color light rearwardly. A light adjusting structure guides the second color light to project rearwardly.