A group of quality of service (QoS) parameters of electronic mail (e-mail) traffic are proposed from users’ perspective. These parameters cover three fields: delay, throughput and usability. Concept and algorithm of each parameter are presented and its effect on user perceptions is described. In order to evaluate the effectiveness of these parameters, an active measurement system is implemented. Measured results show that the group of QoS parameters we proposed can be used to get a comprehensive view of user-perceived e-mail service QoS. A group of quality of service (QoS) parameters of electronic mail (e-mail) traffic are proposed from users’ perspective. These parameters cover three fields: delay, throughput and usability. Concept and algorithm of each parameter are presented and its effect on User perceptions is described. In order to evaluate the effectiveness of these parameters, an active measurement system is implemented. Measured results show that the group of QoS parameters we proposed can be used to get a comprehensive view of user-perceived e-mail service QoS .