To explore the impact of crew integrated optimization on the cost of crew scheduling and efficiency of crew utilization in cross-line operation, a spatio-temporal network was constructed to represent the rules for crew segment connections and shift paths. To determine the rules of crew segment connections, a network model was constructed with the optimization objectives of minimizing the number of shifts and idle time. The network graph search and improved column generation algorithm were designed to obtain shift paths. A mixed crew rostering approach was proposed to verify the impact on crew scheduling. The case study was carried out based on the crew data of some metro lines in a certain city. The results show that the integrated crew scheduling is able to increase the average work efficiency by 1.5%~2.3%. The deadhead segments and crews decrease by 12.18%~24.45% and 1.16％~11.46％. Compared with the phased optimization, the integrated optimization of crew scheduling improves the average work efficiency of shifts and utilization efficiency of crews. It reduces the number of daily shifts and average number of deadhead segments. The integrated optimization approach with the mixed crew rostering mode is able to adapt to the flexible shift cycles and spatiotemporal distribution differences of crew segments, which is conducive to ensuring the balance of shifts and efficiency of crew utilization.