The present invention discloses an optical time domain reflectometer OTDR implementation apparatus and system, where the apparatus includes: M transmitters, configured to transmit M optical waves of different wavelengths, where M is greater than or equal to 2; a processor, configured to control an OTDR detection circuit to load an OTDR detection signal onto a first transmitter, where the first transmitter is configured to only load the OTDR detection signal, and the other M-1 transmitters are configured to transmit a downlink optical signal, where the downlink optical signal is a high frequency signal; the OTDR detection circuit, configured to generate the OTDR detection signal, where the OTDR detection signal is a low frequency signal; and M receivers, where a first receiver is connected to an egress link of the M transmitters, and the other M-1 receivers are connected after a demultiplexer, and are configured to receive multiple uplink signals. By means of the foregoing technical solutions, a problem of detecting reflected light by using an OTDR in a TWDM-PON can be resolved.