pls let me know should i need entry visa for 5 days?

Yes, you need to apply for a L type if you plan to visit mainland China. Your passport, filled application form, a recent six months passport photo, return air ticket and hotel booking are required. Perhaps, your ARC card is required too. You are required to submit your application to the CVASC branches in South Korea.

Contact information of the CVASC branch at Seoul Square
Call: 1670-1888 / 02-6260-8888
E-mail: seoulsquarecentervisaforchina.org