這樣寫對不對？

Based on grammar, both are correct.

The difference is, what you want to emphasize on.

1) Alliance of Pacifism/ The Alliance of Pacifism
would be more on the "Alliance"

and
2)Pacifism Alliance
would be emphasize on "Pacifism"

Just like 1)University of Hong Kong & 2)Hong Kong University. they are both right, but (1) is more like a pro, as in University of Cambridge, University of Oxford...etc

Hope this helps

Pacifism Alliance is more appropriate

1) Alliance of pacifism
2) Pacifism Alliance
Answer 1/ This is absolutely correct in both verbally & in writing, but in writing, officually, we would write The Alliance of Pacifism.
Answer 2/ Okay, we can't say it's wrong, but why don't we use 1) as it's more 正宗.
Correct me if I am wrong.

2007-11-02 09:55:19 補充：
Correction, typing error:officially, not officually.

和平主義聯盟= (2) Pacifism Alliance
This is much easier then
1) Alliance of pacifism

Pacifism Alliance 較為合理