The main steam system pipe and main feedwater system pipe are connected to the steam generator (SG), which are among the most important high-energy pipes in pressurized water reactor nuclear island. Critical safety items are items which is related to the safety of nuclear power station. Measures should be taken to relieve the hazard caused by the rupture of main steam system pipe and main feedwater system pipe to protect the critical safety items. The layout of main steam system pipe and main feedwater system pipe in the same compartment need less room, which can decrease the cost of the construction. It is important to ensure the safety when the two high-energy system pipes designed in the same compartment. Pipe rupture can lead to pipe whip, flooding and so on, which will threaten the safety items nearby. Firstly, the protection criterion for the main team system and main feedwater system pipe is built. Then analysis to the pipe rupture, pipe whip, spray should be carried out to ensure the affection from main steam system pipes and main feedwater system pipes to the critical safety items nearby and to each other. Thirdly measures should be taken, to protect the critical safety items. The safety of HPR1000 nuclear station can be ensured when decreasing the cost by layout the main steam system pipe and main feedwater system pipe in the same compartment.