Geothermal well reinjection is one of the key steps to ensure the sustainable development and utilization of geothermal resources. This paper， in reference to the geological conditions of thermal reservoir， water quality characteristics and geothermal well pipe material in Lankao， Henan province， presents the indoor corrosion observation experiment and PHREEQC geochemical simulation software. The influencing factors of reinjection effect are analyzed from the aspects of chemical precipitation trend， corrosiveness of geothermal water， drilling and well completion technology. Suggestions are put forward to improve geothermal reinjection effect in terms of geothermal water quality treatment， geothermal well pipe material selection， drilling and well completion technology optimization， reinjection temperature， site selection.