This paper is concerned with stability and passivity of negative feedback interconnection of two passive mechanical systems, communicated through communication networks. To model networked negative feedback interconnected mechanical systems, an appropriate network scheduling method based on event-triggered scheme is presented. With this event-triggered scheduling method, the communication bandwidth utilization is considerably reduced while preserving passivity of the interconnected mechanical systems. By constructing a novel discontinuous Lyapunov-Krasovskii functional, a sufficient condition for the networked feedback interconnected mechanical system to be asymptotically stable is derived, where network-induced delays are considered. A new sufficient condition to make the negative feedback interconnected mechanical system in network environments remain passive is correspondingly developed. A numerical example is provided to demonstrate the effectiveness of the proposed method.