Abstract: In view of problem of implementing experiments collaboratively and synchronously by multi-users in existing virtual experiment systems, a communication architecture of collaborative experiment is designed, and a consistent processing method of experiment operation is proposed.To reduce the bandwidth consumption, the communication architecture of collaborative experiment adopted IP multicast.Multicast addresses allocating algorithm and useless multicast addresses recycling algorithm are proposed, so that multicast addresses could be allocated dynamically and recycled.In order to guarantee results consistency on all collaborative participants' sites, experimental operation is attached with environment parameters and sorted by timestamp and priority before being executed.To avoid operational intention conflict, a mechanism of conflict detection on operational intention is proposed.Collaborative experiment has been implemented in existing digital logic virtual experiment system, and experimental results demonstrate that the proposed method can effectively solve the problem of collaborative experiment in virtual experiment system.