The invention discloses a laterally diffused metal-oxide-semiconductor (LDMOS) transistor and a manufacturing method thereof. The LDMOS transistor comprises a semiconductor substrate, an insulation structure, a gate structure and a plurality of floating electrodes. The insulation structure is arranged in the semiconductor substrate; the gate structure is arranged on the semiconductor substrate; and the floating electrodes are embedded in the insulation structure, wherein the floating electrode closest to the gate structure protrudes on one upper surface of the insulation structure, or the gate structure comprises at least one branch portion, which is embedded in the insulation structure; and the floating electrodes are separated with the gate structure.