Background: China has a significant population of bereaved parents (including parents who have lost their only child), who are at a higher risk of developing Prolonged Grief Disorder (PGD). However, there is a notable lack of effective, evidence-based intervention studies tailored for this group. This paper introduces an innovative, localized grief intervention method—Modular Grief Group Counseling— and examines its experimental effects. Method: Modular Grief Group Counseling is based on cutting-edge theories and practices in contemporary grief research, adapted to China’s sociocultural context. The intervention program is standardized and systematic, integrating various intervention elements within the framework of the Dual Process Model. The process spans three months and includes nine group counseling sessions and one individual counseling session. A total of 18 bereaved parents participated in the study, completing assessment questionnaires measuring grief symptoms at three time points: pre-intervention, post-intervention, and three months after the intervention ended. Results: The experimental intervention demonstrated that Modular Grief Group Counseling significantly reduced grief and trauma scores among bereaved parents and lowered the prevalence rates of Prolonged Grief Disorder. Additionally, participants expressed high satisfaction with the intervention. Discussion: As the first evidence-based grief intervention system in China with proven effectiveness, the pilot study of Modular Grief Group Counseling shows considerable potential for application in grief support for bereaved parents.