The invention discloses a self-energy-obtaining dynamic and static human body detector and a micropower low-false-positive and low-false-negative method. The human body detector comprises a monitoring detector body and an environment detector body, and the structure of the monitoring detector body and the structure of the environment detector body are similar; the monitoring detector body comprises a Fresnel lens, a pyroelectric infrared sensor, a signal modulation module, a bistable liquid crystal light valve executing module and a signal collecting, processing, communication, control and self-energy-obtaining module. The pyroelectric infrared sensor sleeved with the Fresnel lens is sequentially connected with the signal modulation module, the signal collecting, processing, communication, control and self-energy-obtaining module and the bistable liquid crystal light valve executing module. A self-energy-obtaining technology overcomes defects of battery / wired power supply, and by means of bright and dark conversion of a liquid crystal light valve, service objects of the human body detector are extended to static people. A differential data algorithm that environment interference is removed from signals of the monitoring detector body through medium-station filtering and by means of the environment detector body enables the false positive rate and the false negative rate to be reduced, and application of micropower improves usability of the human body detector.