Distinct　from　the　resistive-type　control,　such　as　proportional　and　servo　technology,　which　has　substantial　losses,　the　switched　inertance　hydraulic　systems　(SIHSs),　as　the　hydro-mechanical　analog　of　switching　control　topology　in　power　electronics,　can　be　operated　as　efficiently　as　100%　in　theory.　However,　the　analytic　study　has　been　limited　due　to　the　nonlinearity　caused　by　switching　and　throttling,　which　hinders　further　analysis,　optimization,　and　control　of　SIHSs.　Therefore,　with　typical　pressure-boost　topology　as　the　research　subject,　an　analytical　model　including　both　properties　of　nonlinearity　is　proposed　in　this　article.　Fluid　pressure　drop　and　flow　rate　averaging　for　nonlinear　throttle　are　developed　at　first　based　on　the　state-space　averaging　concept.　On　this　basis,　an　average　simplification　of　the　flow　rate　divided　by　the　switched　volume　is　proposed,　followed　by　a　nonlinear　static　model　and　a　linear　dynamic　model　with　quiescent　operating　points　as　the　independent　variables.　Under　more　general　inputs,　the　system＇s　static　output,　dynamic　response,　and　the　affecting　law　of　their　constraints　are　revealed　accurately　in　theory　through　the　novel　model.　Validation　in　simulations　and　experiments　is　presented.　The　proposed　model　provides　significant　theoretical　support　for　improving　and　controlling　the　switched　inertance　hydraulic　systems.