Light chain amyloidosis (AL amyloidosis) is a rare plasma cell dyscrasia characterized by the deposition of insoluble amyloid fibrils in multiple organ systems. The treatment of amyloidosis primarily relies on anti-plasma cell therapy and supportive care. The application of anti-plasma cell therapy has significantly improved outcomes in patients with AL amyloidosis. Standard first-line therapy typically includes daratumumab, bortezomib, cyclophosphamide, and dexamethasone (Dara-BCD), achieving a complete hematologic response in nearly 60% of patients.The depth and speed of the hematologic response are strongly correlated with organ response and overall survival. An early achievement of a complete hematologic response is particularly crucial in cases of AL amyloidosis characterized by significant organ involvement. The median time to a hematologic response for the daratumumab based treatment is only 7-9 days. The retrospective data showed that the hematologic response in Day 7 in Cycle 1 (C1D7) may predict the complete hematologic response rate. In order to validate the conclusion, the investigator design this prospective study.