Swimming　pool　is　a　dynamic　scene　with　great　changes.　It　is　affected　by　bubbles,　light　intensity,　wave　and　other　factors.　In　view　of　the　features　of　the　swimming　pool,　the　underwater　target　tracking　algorithm　based　on　the　combination　of　Mean　Shift　and　Particle　Filter　is　proposed　in　this　paper.　At　first,　according　to　the　kernel　function　and　target　model　in　Mean　Shift,　the　underwater　moving　target　model　is　build　based　on　RGB　histogram.　Then　particle　filter　algorithm　is　used　to　track　moving　target.　In　the　process　of　tracking,　the　distributions　of　the　particles　get　closer　to　the　true　state　of　target　by　using　the　convergence　of　Mean　Shift　on　particles.　The　simulation　results　show　that　the　algorithm　proposed　in　this　paper　achieves　real-time　and　stable　moving　target　tracking　in　the　complex　surroundings　of　swimming　pool.　©　2012　Chinese　Assoc　of　Automati.