Based on observation and reanalysis data, we systematically evaluate global monsoon simulated by the new version of climate system model FGOALS-g3 by applying moisture budget diagnosis and composite analysis, and analyze the advantages and disadvantages compared with FGOALS-g2. Otherwise, the influences of air-sea coupling process on the simulated results are discussed by comparing with the corresponding atmospheric component model GAMIL. FGOALS-g3 reasonably reproduces the basic characteristics of climatology of global monsoon, including annual mean precipitation and circulation, annual cycle modes, monsoon precipitation intensity and monsoon region, but the model underestimates the annual mean precipitation over land monsoon region, overestimates the annual mean precipitation over ocean region, and the simulated spring-fall asymmetric mode of annual cycle is stronger in tropical monsoon region. The results show that the smaller land monsoon region than observation in FGOALS-g3 is associated with the weaker vertical moisture advection (especially the thermodynamic term) in summer. For the inter-annual variability, FGOALS-g3 can reproduce the drier pattern of global monsoon during El Nin ?o year. However, some biases in precipitation anomalies are exist in some monsoon regions. For instance, the precipitation in the West African monsoon region is more than normal, and the precipitation in the Southwest Indian Ocean is a dipole anomaly, both of which are inconsistent with the observation, and the precipitation in the Northwest Pacific monsoon region is more than the observation during El Nin ?o year. Because there is no weak convergence center in the upper layer of western Africa in the simulation, and the simulated maritime continent is warmer than observation, result in the convective center moves westward during El Nin ?o year. In comparison with FGOALS-g2, FGOALS-g3 improves the simulation of monsoon circulation, inter-annual variability of monsoon precipitation, and monsoon-ENSO relationship. Comparing the coupled and uncoupled simulation, most of the biases in the coupled model originate from the atmospheric model itself, and the air-sea coupling process partially improves the simulation of precipitation and circulation of Asian-Australian monsoon region and the tropical Indian Ocean, but the sea surface temperature bias caused by the coupled process enhances dry bias of the Indian Peninsula and the wet bias of the tropical Indian Ocean.