trademark指的是：（註冊）商標;（人的行為或衣著的）特征，標記。
brand指的是：商標，牌子;烙印; 汙名，恥辱。
例句辨析：
trademark
1、The designer bars which have become the new trademark of the city.
已成為這個城市新標誌的時尚酒吧
2、The trademark is registered on the book of the Patent Office.
該商標已在專利局登記註冊。
3、Please identify the registered trademark.
請認明註冊商標。
brand
1、I bought one of the leading brands.
我買了幾個暢銷品牌中的壹種。
2、Advertising agencies are losing their once-powerful grip on brand marketing.
廣告代理公司正逐漸喪失曾經對品牌營銷的有力控制。
3、In office supplies, we're the brand leader.
我們的產品是辦公用品的領導品牌。