The invention discloses a welding-free full-insertion-type LED (light-emitted diode) light source, consisting of a lamp bead, a fixed ring lamp shade, a radiator and a lamp foot, wherein the light bead comprises a lamp bead lens, an LED chip, a fixed lamp holder, a positive pin, a negative pin and an LED support; the fixed lamp holder, the positive pin and the negative pin are arranged in the fixed ring lamp shade; and the lamp bead lens protrudes out of the lamp bead lens. A traditional welding mode is replaced by the connecting mode of threads or fasteners of the radiator and the fixed ringlamp shade, so that the contact of the radiator and the fixed ring lamp shade is realized by the lamp foot and the LED pin in a full insertion type, and the traditional welding mode of the radiator and the fixed ring lamp shade is omitted. For the LED light source, the volume is small, and the largest outer diameter of a largest part, namely the radiator, is only 15mm. The rated current of the lamp bead is 300mA, the rated voltage of the lamp bead ranges from 3.2V to 3.6V, the lightness of the lamp bead is higher than 100 lumen (LM), and the luminance of the light source is enough. In addition, the invention relates to the installation method of the LED light source and a connection lamp holder matched with the LED light source for installing.