A biosensor capable of setting standard measuring values includes a detecting unit coupled with an analog-to-digital converting unit, and the analog-to-digital converting unit is coupled to a processor, and the processor is coupled separately with a setting unit, a display unit, a data storage unit, a reminding unit, and a power supply unit, such that when the detecting unit examines biological testing body, the analog-to-digital converting unit converts test information into a digital data. In the meantime, the processor retrieves the standard values prestored in the data storage unit for a comparison. After the data is processed, the data is displayed by the display unit and the reminding unit. In the meantime, users can use the setting unit to change the default settings of the standard values. The reminding unit will use different lights or sounds to remind users, so that users need not to memorize the meanings of the complicated measured values, but can immediately know about the normal or abnormal signals directly by different lights or sounds.