Abstract: Karst landslides have occurred many times in southwestern mountainous areas in recent years, resulting in the loss of lives and property. Aiming at the karst pipeline action of karst mountain bodies, this paper analyzes its influence on the stability of karst landslides. Firstly, according to field investigations and mechanical analyses, a geological and mechanical model of karst landslides with karst pipelines is established, and a calculation method for the stability coefficient of karst landslides under the action of karst pipelines is proposed. To improve the accuracy of the calculation method, it is considered that the influence of karst pipelines on the stability of karst landslides is reflected in the mechanical effect of karst pipeline flow on rock masses and the deterioration of karst pipelines on rock mass structure. According to Navier-Stokes and Brinkman-extended Darcy equations, the drag force of karst pipelines is deduced, and combined with the water hammer effect, the water hammer force is proposed. Through large-scale numerical direct shear tests and rheological tests, the weakening law of water and karst pipeline development rate on rock mass strength parameters is obtained. Combined with the example of Jiwei Mountain landslide, using the calculation method in this paper, it is concluded that when the karst pipeline is not connected, the Factor of Safety(FOS)=1.204, indicating stability; when the karst pipeline is connected,FOS=1.053, indicating an unstable state; when the karst pipeline is connected and rainfall occurs,FOS=0.965, indicating instability. The conclusion obtained using the calculation method in this paper is consistent with the situation at the landslide site.