In　the　flue　gas　desulfurization　control　system,　the　pH　value　of　the　absorption　tower　slurry　plays　a　vital　role　in　the　desulfurization　efficiency　of　the　system.　Aiming　at　the　non-linearity　and　large　lag　of　the　slurry　pH　change　process　in　the　wet　flue　gas　desulfurization　(WFGD)　process,　a　model　predictive　control　(MPC)　method　based　on　the　dynamic　matrix　control　(DMC)　algorithm　is　designed　to　realize　the　precise　tracking　control　of　the　slurry　pH　value.　The　simulation　results　show　that,　compared　with　the　traditional　PID　control　algorithm,　the　MPC　method　based　on　the　DMC　algorithm　has　better　tracking　ability　and　higher　control　accuracy　for　the　setting　inputs　and　fluctuations　of　the　slurry　pH　value.　This　method　could　further　satisfies　the　system　real-time　control　requirements.　In　addition,　the　model　predictive　control　method　can　effectively　suppress　the　stochastic　interference　in　the　WFGD　process,　and　enhance　the　stability　and　anti-interference　ability　of　the　system.