The invention discloses an abnormal person gathering early warning method and system and a related device. The abnormal person gathering early warning method comprises the following steps: sending a deploying and controlling instruction to acquisition equipment; wherein the deploying and controlling instruction comprises preset feature information of at least one abnormal person; receiving preliminary early warning information from an acquisition device, the preliminary early warning information being generated when the acquisition device determines that there is an abnormal person by comparing the acquired person feature information with preset feature information; based on the received preliminary early warning information, judging whether the current abnormal personnel condition meets apreset aggregation condition or not; and if yes, generating aggregation early warning information of abnormal personnel aggregation. According to the scheme, gathering early warning of abnormal people can be achieved, and public security and stability can be maintained.