With the technological development of multi-branch horizontal wells and complex structural wells， hole cleaning technology is facing new difficulties and challenges. The problems urgent to be resolved are how to solve the problem of cuttings-bed under complex geological conditions and complex well type conditions， to help judge and solve the complex situation downhole. The cuttings transport model is adopted based on the mechanism of cuttings transport. The indoor visualization of cuttings transport experiments was conducted to analyzed the cuttings transport patterns. The results show that the critical velocity of drill cutting is the highest at the well slope angle of 36°， and the drill cutting is most difficult to be carried. The trend of model predicted was validated by comparison with experimental results， and a good accordance was obtained. Its field application also indicates a good agreement between prediction and actual situations， which validated the reliability of this model. The model and experiments are of reference significance for borehole cleaning of large displacement horizontal wells.