This paper investigates the event-triggered dissipative filtering problem for a class of networked semi-Markov jump systems. As a first attempt, the event-triggered communication scheme is introduced to save the limited network bandwidth and preserve the fixed system performance. By using the stochastic analysis, the information on the sojourn time between the mode jumps of the underlying systems is fully considered. By employing time-delay approach, the filtering performance analysis for the considered systems is presented, and then a co-design approach for the event-triggered mechanism and the dissipative filter is adopted such that the filtering error system is strictly dissipative. Finally, a numerical comparative example is used and a mass-spring system model as a realistic example is also provided to show the reduced conservatism and applicability of the proposed filtering scheme.