The purpose of this study was to develop an intervention approach of trauma therapy. A case study method was used to explore the process and effects of sandplay therapy for psychological trauma counseling from a posttraumatic growth perspective. A total of 20 sandplay sessions were conducted with a postoperative cervical cancer patient in recovery. After the counseling sessions, the client’s score on the PCL-C decreased from 33 to 21, and the score on the PTGI increased from 24 to 67. The sandplay process went through four stages: presentation and preparation, introspection and resistance, regression and connection, and growth and integration. Meanwhile, an inductive analysis was conducted on the changes of thematic, character portraits and time clues of the sandplay works. The results showed that after receiving sandplay therapy, the client has developed from low level of post-traumatic growth to higher level of post-traumatic growth and the post-traumatic stress symptoms were relieved. In conclusion, the counseling was effective and sandplay therapy showed particular mechanisms in this process.