Drug clinical trials constitute a critical link in new drug development and an essential means to verify the safety and efficacy of pharmaceuticals. The protection of participants’ rights and interests and the prevention of risks directly affect the scientific ethics and social credibility of the trials. Vulnerable groups， due to restricted autonomous decision-making capacities or special social status， are more susceptible to safety risks. Children are a typical representative of vulnerable groups. Their physiological particularities， cognitive limitations， and dependence collectively epitomize the universal protection demands of vulnerable research participants. Taking children as an instance， this paper analyzes the current weak links in the protection of pediatric research participants. Integrating advanced international experience with domestic practical demands， it comprehensively identified protection risk points at every stage and constructed a multi-stakeholder collaborative mechanism for the full-process protection of pediatric research participants. This mechanism incorporated seven main entities， including drug regulatory authorities， sponsors， researchers， and ethics committees， covering the pre-trial， intra-trial， and post-trial phases to meet the requirements of full-chain and multi-dimensional protection. It provided references for the subsequent establishment of a systematic protection mechanism for vulnerable populations.