The utility model discloses an FTTx centralized type optical measuring system providing a device capable of detecting quality of an optical fiber line timely. The FTTx centralized type optical measuring system comprises an optical fiber coupler module, a monitoring device, a client computer, a switchboard, a server, and an alarming lamp. The client computer, the switchboard, the server, and the alarming lamp are remotely controlled. The optical fiber coupler module and the monitoring device are parallely connected together. The monitoring device comprises an OTDR and an optical switch, which are respectively connected with the switchboard, and are connected with the client computer, the server and the alarming lamp by the switchboard. By using the FTTx centralized type optical measuring system, the quality of the external optical network can be regularly or continuously detected in a central machine room, and when faults are detected, the fault types can be analyzed and alarmed. The FTTx centralized type optical measuring system has advantages of simple technology and convenient use.