1. A system for detecting a global harmful video, the system comprising: at least one processor configured to: determine harmfulness of learning video segments from video learning information to analyze occurrence information of harmful learning video segments among the learning video segments, and generate a global harmfulness determination policy based on the analyzed occurrence information; and determine harmfulness of input video segments from information of an input video to analyze occurrence information of harmful input video segments among the input video segments, and determine whether the input video is harmful or not based on the analyzed occurrence information of the harmful input video segments and the generated global harmfulness determination policy, wherein the at least one processor is further configured to determine harmfulness of the learning video segments; analyze the occurrence information of the harmful learning video segments based on the harmfulness determination results of the learning video segments to thereby derive occurrence frequencies, occurrence continuities and occurrence probability values of the harmful learning video segment; and generate the global harmfulness determination policy by determining weights for each of the occurrence frequencies, the occurrence continuities and the occurrence probability values of the harmful learning video segments.