In-situ stress is a key parameter in the sweet-spot assessment, horizontal well arrangement and fracturing design in the exploration and development of unconventional oil and gas reservoirs. At present, the elastic model based on in-situ stress evaluation technology which is used for conventional reservoirs is applied to shale reservoirs at home and abroad while the effects of rheological behaviors on the distribution laws of in-situ stress in shale reservoirs are not taken into consideration, which brings a larger error to the evaluation result of in-situ stress of shale reservoirs. In this paper, a new in-situ stress evaluation method base on the rheological model was put forward to increase the evaluation and calculation accuracy of in-situ stress parameters. Then, the variation laws of rock rheological parameters with the depth were determined by using the rock mechanical parameters obtained from cross-dipole acoustic logging data, referring to the related experimental results. And combined with the burial history of the basin and the strain rate of the crust, the in-situ stress profile of Well AY-1 in the Qianbei area of Guizhou Province was established. Finally, the in-situ stress evaluated by the new method was compared with the one measured in the mini frac and the one determined by the stress polygon method. And it is indicated that the in-situ stress profile of Well AY-1 predicted by the new method is consistent with the test result and its in-situ evaluation result presents a good corresponding relationship with the result of Gamma logging. As the content of clay mineral or organic matter increases, the horizontal principal stress difference decreases, indicating that the in-situ stress evaluation result by the new method is in better accordance with the distribution law of true in-situ stress.