The present invention provides an outdoor lamp having at least one lighting unit which can be powered by a solar energy battery unit electrically connected to each of the at least one lighting unit. Each lighting unit has a base, at least one light emitting diode (LED) on the base. A transparent cover is mounted on the base and partially coated or mixed with luminescent material. By using the solar energy battery unit and the LED, the lamp is economical and efficient in use. Moreover, the luminescent material keeps the lamp on lighting after the solar energy battery unit is exhausted.