A power detection apparatus is provided. The power detection apparatus includes a first current processing circuit and a second current processing circuit. The first current processing circuit is configured to provide a dynamic bias voltage at a bias terminal in response to a variation of a system power. The second current processing circuit is coupled to the first current processing circuit and is biased under the dynamic bias voltage for outputting a power good signal at an output terminal to represent that the system power is ready when the dynamic bias voltage is greater than a threshold voltage.