Abstract: The content of clay is high and it's water sensitive, so it can easily expand during the water injection. In order to solve this problem, the compressive;expansion technology was researched. Based on lab experiments, physical and chemical parameters of the compressive-expansion agent were evaluated including compressive-expansion and anti-swelling properties, core pellets stability and corrosion properties, etc. Also, application was evaluated by constructing two water injection wells. As a result, the compressive-expansion technology can take effect in decompression and augmented injection, and can increase injected wa-ter volume.