The invention is suitable for the field of displaying control, and particularly relates to a displaying area self-adaptive adjusting device based on an OLED flexible screen. According to the displaying area self-adaptive adjusting device, the expansion scale of the LED flexible screen is detected through a capacitive gate transducer; an expansion area of the OLED flexible screen and a displaying resolution which corresponds with the expansion area are calculated through a control circuit according to the expansion scale; and proportional zooming processing is performed on an image input signal so that image displaying covers the current expanded displaying area, thereby realizing high displaying clarity of the OLED flexible screen and improving user experience.