Eight Ml≥7.0 earthquakes have occurred around the Bayan Har block, NW Tibet, China, since 2000, resulting in a large number of casualties and countless economic loss. Near the western boundary of the Bayan Har block, four Ml≥6.0 Yutian earthquakes have occurred from 2008 to 2020. Stress interactions among them are comprehensively investigated by applying the ETAS (Epidemic-Type Aftershock Sequence) model and calculating (Coulomb failure stress change). The viscoelastic induced by proceeding Yutian earthquakes on hypocenters of the 2012, 2014 and 2020 Yutian earthquakes are -1.5004×10^-4 , 3.5820×10^-3 and 1.4770×10^-1 MPa, respectively. The background probabilities of the 2008, 2012, 2014 and 2020 Yutian earthquakes are 0.87, 0.97, 1.5×10^-3 and 8.7×10^-5, respectively. Combining those two independent approaches, we conclude that the 2008 and 2012 Yutian earthquakes are more like background earthquakes and that the 2014 and 2020 Yutian earthquakes were triggered by the proceeding Yutian earthquakes.