The invention discloses an energy-saving street lamp. The energy-saving street lamp comprises a lamp post and a lamp holder. The lamp holder is connected to the top end of the lamp post. An LED lamp and a storage battery used for providing electric energy for the LED lamp are installed inside the lamp holder. The lamp post is further connected with a solar panel, and the solar panel is electrically connected with the storage battery. The lamp post is further connected with a water storage tank, and a rainwater collection hopper is arranged above the water storage tank. A sprinkler pump and a motor used for providing power for the sprinkler pump are arranged inside the water storage tank. The motor is electrically connected with the storage battery. The water storage tank is provided with awater spraying pipe which sprays water outwards. The water spraying pipe is connected with the sprinkler pump and is further provided with a power control valve. The lamp post is further provided with a control switch. The control switch is electrically connected with the motor and the power control valve. According to the energy-saving street lamp, the water storage tank is used for collecting rainwater, sprinkling is conducted when road sprinkling is required, and water resources can be greatly saved.