The interaction and influence mechanism between oasis and desert is an important component of landscape geography in arid areas. The oasis of Hong Yashan Region (OHR) is a typical tail oasis continental river in northwestern China, located in the northern temperate arid desert area belonging to an extremely arid continental climate. In this paper, the spatial distribution information of the oasis in Hong Yashan region was extracted through obtaining remote sensing imagery in 1988, 1992, 1995, 2000, 2004, 2008a, 2013, and 2016. The quantitative models and geographical grid method were used to analyze area changes, direction migrating, intensity fluctuating, and forces driving in order to understand the change mechanism. The results show that during 1988-2016, the oasis area increased first and reached the peak value of 1,343.67 km² in 2004, then decreased to the valley value of 1,026.66 km² in 2008, and then increased again to 1,077.59 km² in 2016. The dominant factors which affected oasis changes were distinct in the different periods and positions, and they interacted with each other. We found that the dynamic changing process of an oasis was the result of natural and human activities. The growth of oasis both in area and distribution have been affected by natural factors through water resource changes.