The invention discloses a controlling method for a digital instrument. The method comprises the following steps that a measurement value is acquired; a working mode of the instrument is determined according to the working mode which is selected by a user, wherein the working mode comprises a simple mode, a user-defined mode and a compensation calculation mode; according to the working mode of theinstrument, a measurement interval of the measurement value is obtained, wherein the measurement interval is a uncertainty degree interval or a precision interval; when the measurement value is displayed, the instrument is controlled to display the measurement interval of the measurement value. According to the embodiment, the instrument is controlled to display the measurement value, meanwhile, the measurement interval can be displayed, more true, accurate and valid information is provided for the user, accurate and high-precision reading requirements are guaranteed, and the reliability and applicability of the instrument are improved. The invention further discloses a control device of the digital instrument and the digital instrument with the control device.