The Asian monsoon evolution has been significantly influenced by the orbital forcings, especially by the insolation variations induced by precession.From 1980s, many observations and simulations, particularly the recent stalagmite records and long-term transient experiments, have indicated that the precession forcing can result in a quasi-20 ka cycle in the variations of Asian monsoon.However, debates still exist on the mechanism how precessioninduced insolation drives the Asian monsoon climate, with a focus on two hypotheses of "zero-phase" and "southern latent heat".The "zero-phase" hypothesis proposes that the evolution of Asian monsoon is dominated by the northern summer insolation and the "southern latent heat" hypothesis also emphasizes the influence of latent heat from southern Indian Ocean associated with southern summer insolation.These hypotheses have been both supported by some geological evidence, thus, they are eagerly required the examinations of numerical simulations especially the transient ones.Owing to the restriction of computational resources, most of previous paleo-monsoon simulations are "snapshot" or "time-slice", which usually limited to some specific periods.