The invention discloses an LED light source railway signal bulb and a special lamp base. The bulb comprises a cylindrical bulb body; the cylindrical bulb body is provided with a heat dissipating piece at the front part, a clamping groove for fixing the bulb body at the back part, LED chips and a transparent cover at the front end and a wire passing head and a wiring ring at the back end; and the clamping groove is provided with protrusions for identifying colors of the LED chips. The six LED chips are divided into a main chip set and a secondary chip set; each set consists of three chips horizontally and transversely arranged; the secondary chip set is positioned above the main chip set; and the adjacent LED chips reach 0.5 mm of horizontal gaps and 1.5 mm of vertical gaps. The lamp base comprises a semicircular clamping ring A and a semicircular clamping ring B which are hinged by one sides; and the clamping groove of the LED light source railway signal bulb is fixed in an annular cavity surrounded by the clamping ring A and the clamping ring B. The clamping ring A is fixed on a slide base. The clamping ring A is provided with openings with the depth of 1 mm; and the position and the number of the openings correspond to those of the protrusions in the clamping groove of the LED light source railway signal bulb. The bulb is continuous in light emitting intensity to facilitate signal displaying; and the lamp base can prevent the bulb from shaking to adapt to the working environment with strong vibration, the bulb is convenient to replace, and the performance is safe and reliable.