For　the　present　investigations　of　the　off-design　performance　of　organic　Rankine　cycle　systems,　which　are　mainly　based　on　indirect　parameters　such　as　temperature　and　pressure,　it　is　difficult　to　provide　direct　theoretical　guidance　for　the　actual　operation　of　the　system.　Therefore,　this　paper　introduces　a　novel,　directly　regulated　coupling　model　based　on　a　quasi-two-stage　single　screw　expander　and　a　multistage　centrifugal　pump.　In　addition,　to　enhance　the　matching　between　the　expander　and　the　pump　during　the　regulation,　the　coupled　model　is　optimized　using　the　particle　swarm　optimization　algorithm.　The　results　reveal　that　the　net　efficiency　initially　increases　and　then　decreases　when　exploring　regulation　strategies　for　the　expander　and　the　pump,　suggesting　the　existence　of　optimal　operating　points.　Specifically,　after　applying　the　particle　swarm　algorithm,　the　net　efficiency　reached　13.23　%　at　an　expander　speed　of　5076　RPM　and　a　pump　frequency　of　46.8　Hz,　reflecting　a　better　match　between　the　pump　and　expander　regulation　with　the　heat　source　conditions.　For　instance,　at　a　heat　source　temperature　of　200　degrees　C,　the　net　efficiency　increased　by　up　to　1.45　%　compared　to　the　original　results.