Go back home and planing to purchase a one way ticket

Hello it’s me again, I’m planning to go back home and I’ve been using permanent resident visa here in China , I’m going home purchasing only one way plane ticket. My question is, if I’m going back here in China am I allowed to purchase one way ticket from my country or do I need to purchase round trip ticket even if my resident visa not has been expired? If I do purchase one way ticket do immigration here in China will hold me for that reason? Thank you so much.