This application provides a receiver optical sub-assembly, a bi-directional optical sub-assembly, and an optical network device to improve anti-electromagnetic crosstalk performance of the receiver optical sub-assembly. The receiver optical sub-assembly includes: a photodiode, a trans-impedance amplifier, and a first filter component. The photodiode is configured to convert an optical signal into an electrical signal, a positive electrode of the photodiode is connected to an input terminal of the trans-impedance amplifier, and a negative electrode of the photodiode is configured to connect to a power supply. The trans-impedance amplifier is configured to amplify the electrical signal output by the photodiode, a power terminal of the trans-impedance amplifier is configured to connect to a power supply, and a first ground terminal of the trans-impedance amplifier is configured to connect to an external ground. A first terminal of the first filter component is connected to a second ground terminal of the trans-impedance amplifier, and a second terminal of the first filter component is configured to connect to the external ground.