The invention discloses a method, a circuit and a device for detecting poor contact of a terminal of a smart electric meter. The circuit comprises a current sampling circuit, which is arranged betweenincoming and outgoing line terminals of a live line and a null line, and is respectively connected with a pre-detection circuit and a signal conditioning circuit to collect a live line current signaland a null line current signal; the pre-detection circuit is connected with a detection chip to respectively obtain a first high-frequency signal from the null line current signal and a second high-frequency signal from the live line current signal; the signal conditioning circuit is connected with the detection chip to adjust the live line current signal and the null line current signal respectively, so as to obtain a corresponding first adjustment signal and a corresponding second adjustment signal; and the detection chip determines whether there is a suspected arc based on the first high-frequency signal and the second high-frequency signal, respectively samples the first adjustment signal and the second adjustment signal when the suspected arc exists and judges whether the terminal issubjected to poor contact. Therefore, whether the terminal is loose can be discovered in the early stage, and then the detection sensitivity and safety are improved.