Research conclusions:Based on the analysis of the bandwidth requirement of the PIS wireless network，only the 802.11a technology or 802.11g technology can be adopted in PIS． The interference between PIS and CBTC can be avoided when 802.11a technology is adopted in PIS，and the interface and implementation of project are easier．But when 802.11g technology is adopted in PIS，the frequency of PIS should be different from the frequency of CBTC，and the project interface is increased．Possible interference from other wireless network should be considered simultaneously．