Magnetic circuit system and loudspeaker

The utility model discloses a magnetic circuit system. The magnetic circuit system comprises a magnetic conductive assembly, a magnet assembly, and a lower magnetic conductive plate which are fixedly connected in sequence from top to bottom. The magnetic conductive assembly comprises an inner magnet ring and an outer magnet ring sleeved on the outer side of the inner magnet ring. A second annular gap is formed between the inner magnet ring and the outer magnet ring. A first annular gap is communicated with the second annular gap in longitudinal direction. The utility model also discloses a loudspeaker. The magnetic circuit system and the loudspeaker can effectively reduce volume of the loudspeaker, and meanwhile performance of the loudspeaker is improved.