如果不直译，意译也是可以的。
英语里有一句谚语 “A black plum is as sweet as a white.（乌梅白梅一样甘甜。）”就和邓小平的“黑猫白猫论”有异曲同工之妙。另外，对于西方人来说，这样的译法也会让他们觉得亲切且便于理解。
如果坚持要直译，上面的同仁已经翻译得很好了。我这里还提供另外几种直译：
1.It does not matter if a cat is black or white. A cat that catches
mice is a good cat.
2.Black cat or white cat, the one that catches mice is the good cat.
3.All cats are good, white or black, as long as they can catch mice.






All cats are good, white or black, as long as they can catch mice.

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Note added at 9 hrs (2007-01-07 12:23:11 GMT)
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我注意到提問的Jennifer Li是臺灣人，可能看不懂簡體，所以再把我的回答轉化成繁體。

如果不直譯，意譯也是可以的。
英語裏有一句諺語 “A black plum is as sweet as a white.（烏梅白梅一樣甘甜。）”就和鄧小平的“黑貓白貓論”有異曲同工之妙。另外，對於西方人來說，這樣的譯法也會讓他們覺得親切且便於理解。
如果堅持要直譯，上面的同仁已經翻譯得很好了。我這裏還提供另外幾種直譯：
1.It does not matter if a cat is black or white. A cat that catches
mice is a good cat.
2.Black cat or white cat, the one that catches mice is the good cat.
3.All cats are good, white or black, as long as they can catch mice.