This is a prospective, open, dose-exploring clinical study of Lutetium [177Lu]-FAP-75 in the treatment of patients with advanced solid tumors. The study was divided into two stages, the first stage was dose exploration study, and the second stage was case expansion study. In the first phase of this study, several dose groups were designed. Subjects may receive only one of these doses and may not receive multiple doses in the same subject. The drug was administered every 6 weeks, and the DLT observation period was 6 weeks after the first dose. Firstly, the first dose safety introduction of human body was carried out. Based on the results of the preclinical study of this product, an appropriate number of enrolled subjects in the first and second stages were selected to enter the PK and radiation dosimetry detection groups. After the end of the DLT observation period, subjects who met the criteria for continued dosing were allowed to continue to receive the investigational drug therapy for subsequent cycles. For all participants enrolled in this study, the study process included a screening period, a treatment period and a follow-up period. In the course of the trial, extended studies of other tumor species can be conducted based on new advances and results of clinical studies of similar drugs to further explore the safety, tolerability and initial effectiveness of specific tumor types.