The invention discloses an adjusting method and adjusting system for imaging quality of a digital domain TDI (Time, Delay and Integration) camera. The adjusting method comprises the steps of determining a pre-photographing area; determining an actual gray average value of the pre-photographing area according to pre-photographing exposure time and pre-photographing gain; determining a product of expected exposure time and an expected gain of a TDI imaging area; determining integration series and integration time of the TDI imaging area; determining the expected gain and the expected exposure time; determining an image of the current TDI imaging area according to the integration series, the integration time, the expected gain and the expected exposure time; and judging whether a next pre-photographing area exists or not, if the next pre-photographing area exists, updating the pre-photographing exposure time and the pre-photographing gain, otherwise, determining a photographing image of the TDI camera according to the image of each TDI imaging area. According to the adjusting method and the adjusting system provided by the invention, the in-orbit self-adaptive adjustment for the imaging quality of the digital domain TDI camera can be finished according to an actual photographing environment.