This　paper　presents　a　compact　aggregated　unit　model　(CAUM)　for　short-term　hydro　power　generation　scheduling.　The　CAUM,　which　is　obtained　based　on　optimal　piecewise　linear　approximation,　represents　the　relationship　between　the　maximum　power　generation　level　of　the　plant,　total　water　discharge　and　the　average　storage　of　the　reservoir.　Different　from　the　real-time　optimal　dispatch　of　the　hydropower　system,　the　CAUM　is　an　off-line　optimization.　Meanwhile,　the　aggregation　of　the　individual　unit　simplifies　the　short-term　hydro　power　generation　scheduling　since　all　the　individual　unit　related　constraints　are　removed.　By　using　the　CAUM,　the　optimal　power　generation　level　can　be　rapidly　determined　and　the　short-term　hydro　power　generation　scheduling　would　be　greatly　simplified.　Numerical　testing　results　demonstrate　that　the　method　is　effective.