This study explores how windows with a green view might affect the mental health (i.e., depressive/anxiety symptoms) of home-isolated populations. An online survey was conducted among 508 adults isolated under government quarantine policies for COVID-19 emergency pandemic control between 10 and 20 January 2022 in Xi’an, China. Structural equation modeling was employed to identify the pathways from green view through windows to isolated people’s depressive/anxiety symptoms. The relative frequency of plant/water exposure through windows was associated with fewer depressive/anxiety symptoms. Home-isolated people during COVID-19 reported better mental health when they were exposed to more natural settings. These findings could inspire public health authorities to adopt nature-based solutions to mitigate the adverse mental health consequences of isolated populations during the pandemic.