Abstract: An LED street lamp has a lamp body, at least one LED module and a power supply. The lamp body includes at least one heat dissipating portion and a connecting portion. Each of the at least one heat dissipating portion has two main fins. The main fins are crossed to divide each of the at least one heat dissipating portion into four fan-shaped regions. Each fan-shaped region has multiple auxiliary fins and multiple ventilation channels. Each of the at least one LED module is secured to one of the at least one heat dissipating portion of the lamp body. The power supply is mounted on the connecting portion of the lamp body. With the above-mentioned structure, the LED street lamp can provide improved heat dissipation and dust does not easily accumulate in the ventilation channels.