The invention discloses a detection circuit and fine adjustment method of an Eflash and the Eflash. The detection circuit of the Eflash is suitable for detecting the programming voltage of the Eflash in the programming state or the erasing voltage of the Eflash in the erasing stage. The detection circuit comprises a test channel selection circuit and a voltage comparison circuit, wherein the test channel selection circuit is coupled with a fixed test point, and an enable signal is input to the test channel selection circuit; the voltage comparison circuit is coupled with the test channel selection circuit. When the enable signal is in a first logic level, the fixed test point detects the programming voltage or the erasing voltage through the test channel selection circuit; when the enable signal is in a second logic level different from the first logic level, the fixed test point is coupled to the voltage comparison circuit through the test channel selection circuit, and the programming voltage or the erasing voltage is compared with the reference voltage on the fixed test point through the voltage comparison circuit to generate a detection result; the detection result is suitable for being transmitted to a fine adjustment circuit. By means of the detection circuit and fine adjustment method of the Eflash and the Eflash, the detection time of the programming voltage or the detection time of the erasing voltage can be greatly shortened.