An optical access system, comprising: an optical access device and at least one physical, PHY, processing entity connected to the optical access device, wherein the optical access device is configured to: receive first downlink data, perform first processing on the first downlink data at a media access control, MAC, layer in the optical access device to obtain second downlink data in a form of a digital electrical signal, and send, in a form of a digital optical signal, the second downlink data in a form of a digital electrical signal to the at least one PHY processing entity; and each PHY processing entity in the at least one PHY processing entity is configured to: receive the second downlink data that is in a form of a digital optical signal and that is sent by the optical access device, perform second processing on the second downlink data in a form of a digital optical signal at a PHY layer to obtain third downlink data in a form of an analog electrical signal, and send the third downlink data in a form of an analog electrical signal to a cable modem, CM; wherein the optical access device comprises a switching control unit, and an uplink processing unit and a MAC resource processing unit that are connected to the switching control unit, wherein the uplink processing unit is configured to: receive the first downlink data, and send the first downlink data to the switching control unit; the switching control unit is configured to: receive the first downlink data sent by the uplink processing unit, send the first downlink data to the MAC resource processing unit, receive the second downlink data that is in a form of a digital electrical signal and that is sent by the MAC resource processing unit, and send, in a form of a digital optical signal, the second downlink data in a form of a digital electrical signal to the at least one PHY processing entity; and the MAC resource processing unit is configured to: receive the first downlink data sent by the switching control unit, perform first processing on the first downlink data at the MAC layer to obtain the second downlink data in a form of a digital electrical signal, and send the second downlink data in a form of a digital electrical signal to the switching control unit; wherein the optical access device further comprises a video resource processing unit connected to the switching control unit, and the first downlink data is video data; the switching control unit is specifically configured to: receive the video data sent by the uplink processing unit, send the video data to the video resource processing unit, receive the video data that is processed and sent by the video resource processing unit, send the processed video data to the MAC resource processing unit, and receive the second downlink data that is in a form of a digital electrical signal and that is sent by the MAC resource processing unit; the video resource processing unit is configured to: receive the video data sent by the switching control unit, perform third processing on the video data to obtain processed video data, and send the processed video data to the switching control unit; and the MAC resource processing unit is specifically configured to: receive the processed video data sent by the switching control unit, perform first processing on the processed video data at the MAC layer to obtain the second downlink data in a form of a digital electrical signal, and send the second downlink data in a form of a digital electrical signal to the switching control unit.