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

Here is Why You Need An Adapter

The outlet and plug type used in Namibia are D and M and in China are A, C and I. This is how they look like.

China

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

Type A

Type C

Type I

Namibia

In Namibia, outlets of type D and M are in use.

Type D

Type M