Quality of service monitoring method, device and system are provided. The method includes receiving a data packet of a service. The data packet is generated during a service interaction between a first device and at least one second device. The method also includes determining a service type of the data packet based on an application layer message and/or a transmission layer message of the data packet. The method also includes determining a quality of service indicator according to the service type, and acquiring analysis data in the data packet according to the quality of service indicator. The method also includes determining the quality of service of the service based on the analysis data.