The invention relates to a weak light and weak wind charging control circuit and belongs to the electric control energy saving technical field. Storage batteries are configured for photovoltaic power generation and wind power generation, while, when the voltage of generated power is lower than the voltage of the storage batteries under the condition that light is weakened or wind is weakened, charging cannot be realized, and at this moment, light energy or wind energy is not utilized. The weak light and weak wind charging control circuit of the invention is composed of a window comparator, a booster and a synchronous control circuit; when the voltage of generated power is higher than the voltage of the storage batteries, the normal charging of the storage batteries is not influenced, and when the voltage of the generated power is lower than the voltage of the storage batteries, a voltage boosting circuit is started, and the storage batteries can be continuously charged, and the energy of weak light and weak wind can be utilized; and since power generated under weak light and weak wind conditions is weak, the synchronous control circuit is additionally adopted, so that electric energy transmission efficiency can be increased. The weak light and weak wind charging control circuit is especially suitable for unattended small-scale power supply systems, such as photovoltaic power generation and wind power new energy powered street lamps and monitoring systems of high-rise towers.