Abstract: A mathematical model on cuttings transportation of dual layer stabilizing in the highly inclined well is established based on the Law of Mass Conservation and Momentum Theorem,taking the fines spreading in the suspension layer and fluid pressure drop in the cutting bed into consideration.Stimulation studies were carried out from such aspects as annular velocity,hole inclination,bed fraction and additional pressure drop due to fluid flow in the cutting bed,etc.,and the results showed that,with the increase of bed fraction and annular velocity,cutting fines obtains good suspension;with the increase of hole inclination,the concentration of fines in suspension layer decreases;while the cutting bed has larger distribution area,fluid pressure drop across the cutting bed should be considered in hydraulic design of the highly inclined well.