The　control　of　rail　pressure　is　quite　important　in　the　common　rail　fuel　system.　Generally,　the　rail　pressure　control　strategy　is　a　combination　of　feedforward　control　and　proportional-integral-derivative　feedback　control.　A　lumped　parameter　model　of　the　common　rail　fuel　system　is　built.　Theoretically,　the　three　main　factors　that　affect　the　rail　pressure　are　engine　speed,　rail　pressure,　and　fuel　injection.　With　these　factors　as　the　control　parameters,　the　feedforward　control　logic　is　established.　Then,　with　the　basic　fuel　amount　as　the　proportional-integral-derivative　control　parameter,　the　feedback　control　strategy　is　improved.　The　feedforward　control　is　used　to　determine　the　basic　fuel　amount;　the　proportional-integral-derivative　feedback　control　is　used　to　fine-tune　the　basic　fuel　amount　based　on　the　deviation　of　target　rail　pressure　and　real　rail　pressure.　Compared　with　only　proportional-integral-derivative　feedback　control,　the　computation　load　of　feedback　control　is　reduced　and　the　response　speed　is　increased.　In　addition,　experiments　based　on　a　common　rail　fuel　system　test　rig　are　completed.　The　results　show　that　the　fuel　efficiency　of　common　rail　fuel　pump　decreases　with　pump　speed,　and　rail　pressure　increases.　The　steady-state　rail　pressure　fluctuations　are　effectively　reduced　and　the　dynamic　control　precision　of　the　common　rail　fuel　system　increases　when　the　optimized　control　method　is　adopted.