You Do Need power plug adapter while traveling from Guinea to China.

Here is Why You Need An Adapter

The outlet and plug type used in China are A, C and I and in Guinea are C, F and K. This is how they look like.

Guinea

In Guinea, outlets of type C, F and K are in use.

Type C

Type F

Type K

China

In China, outlets of type A, C and I are in use.

Type A

Type C

Type I