They're currently looking at two sites in Utopia Planitia. Each landing site will have a landing eclipse of 40 by 100km.
This region has a cool feature in;
Utopia Planitia may have been extensively resurfaced by mud flows, so it is an interesting place to investigate potential past subsurface habitability. Alfred McEwen
This is an edited version of this image to include a rough approximation of the Tianwen-1 landing sites.