In　the　rebuilding　of　old　city,　because　of　the　complexity　of　ambience,　foundation　pit　excavation　can　cause　disturbance　to　the　soil,　and　bring　the　distortion　of　retaining　structure,　the　stability　of　foundation　pit　could　be　lost.　Taking　an　example　about　foundation　pit　excavation　in　complicated　environment,　the　monitoring　scheme　of　foundation　pit　excavation　is　discussed;　the　monitoring　result　is　and　analyzed　so　as　to　guide　construction　excavation.　The　safety　of　retaining　structure　and　ambience　is　ensured;　informational　construction　is　made.