A method for solar power energy management with intelligent selection of operating modes classifies the power energy of a solar cell and an reserved power of a rechargeable battery into multiple power level ranges, and determine to supply power to a load in accordance with various combinations of the power level ranges of the solar cell and the rechargeable battery to avoid energy waste. When the solar cell is in a “sufficient” power level range, the power energy of the solar cell is simultaneously supplied to the load and stored in the rechargeable battery. When the solar cell is in an “insufficient” power level range, all the power energy of the solar cell is selectively supplied to the load or charged to the rechargeable battery. When being in a “poor” power level range, the power energy of the solar cell can still be charged to the rechargeable battery.