The present invention discloses an analog photovoltaic power circuit, including: a photovoltaic device group for receiving photo energy to generate an input voltage, the input voltage corresponding to an input current; a power stage circuit for receiving the input voltage and generating an output voltage; an optimum current or voltage estimation circuit for receiving a predetermined voltage and estimating an optimum current or voltage point corresponding to an optimal output point according to a direction of variation of the input current and a direction of variation of the power generated by the photovoltaic device group; and an analog comparison and control circuit for comparing the optimum current or voltage with the input current or voltage, to thereby control the operation of the power stage circuit.