A biological detection chip, a biological detection device, and a detection method thereof are disclosed. The biological detection chip includes a first base substrate and a plurality of detection units arranged in an array along a row direction and a column direction on the first base substrate. Each of the plurality of detection units includes a thin film transistor and an electrode, the thin film transistor is on the first base substrate and includes a gate electrode, a source electrode, and a drain electrode, and the electrode is on a side of the thin film transistor away from the first base substrate and is connected to the drain electrode, and the electrode is configured to carry a biological material to be detected.