A　novel　optical　system　for　detecting　and　controlling　the　time-delay　value　of　probe　light　in　the　femtosecond　pulse　pump-probe　measurements　is　presented　based　on　the　simultaneous　phase-shifting　interferometry　scheme.　The　intensity　distributions　of　interference　pattern　are　calculated　based　on　the　Jones　theory　to　optimize　the　optical　system,　by　which　the　analytical　expressions　for　phase-shifting　length　between　the　neighboring　interferograms　and　the　relevant　phase-delay　value　are　derived.　To　meet　the　requirement　of　practical　application,　possible　latent　errors　in　the　process　of　detecting　time-delay　are　analyzed.　In　particular,　a　minimum　time-resolution　with　attosecond　level　at　800　nm　wavelength　was　achieved.　The　results　show　that　this　system　satisfies　the　requirement　of　femtosecond　pulse　pump-probe　high-precision　measurement.