The invention relates to an oscillation circuit for realizing adjustable duty ratio and frequency based on an OTA. The oscillation circuit comprises a capacitor charge and discharge circuit structure, an OTA circuit structure and a digital control circuit structure. Comparison of input ends is realized by utilizing the OTA circuit structure. The comparison result influences charge and discharge of a capacitor in the capacitor charge and discharge circuit structure so that an output signal of oscillation is obtained. The digital control circuit structure determines working of the whole oscillation circuit and can adjust duty ratio and frequency of an oscillation signal. The oscillation circuit for realizing adjustable duty ratio and frequency based on the OTA has advantages that duty ratio and frequency of the oscillation signal can be adjusted, power consumption is low and response is fast.