从句法角度上讲，定语从句是次要成分，但在语言的作用上，却有着重要的地位。由于合同语言要求准确和规范，如果缺少了定语从句，合同条款的语义往往很难达意完整。因此，定语从句在合同英语中的应用较广泛。英语的定语从句可分为限定性定语从句和非限定性定语从句两大类。现就这两类定语从句的处理方法分述如下：

(1)限制性定语从句的翻译：限制性定语从句与先行词的关系十分密切，少了它，句义往往不够完善。在翻译这类从句时，往往釆用合译的手法，常把限制性定语从句译成汉语的“……的”结构，并置于被修饰词之前。例如：
①If the Buyer is unable to sell out the amount of goods which he has agreed to purchase from the Seller，the Buyer may reduce the quantity of goods to be delivered to him by giving written notice thereof to the Seller before the shipment is made.
如果买方不能销售他巳同意从卖方所购数量的货物，买方可以书面通知卖方减少发货数量，再要求卖方发货。
②Within 15 days after the arrival of the goods at destination，should the quality, specifications, or quantity be found not in conformity with the stipulations to the Contract except those claims for which the insurance company or the owners of the vessels are liable, the buyer shall, on the strength of the Inspection Certificate issued by the China Import and Export Commodity Inspection Bureau，have the right to claim for replacement with new goods，or for compensation，and all the expenses shall be borne by the Seller.
货物运抵目的港之日起，15天内，除应由保险公司和船主负责的索赔外， 如果发现货物的质量、规格或数量与本合同规定不符，买方凭中国进出口商品检验局出具的检验证书，有权要求更换新货，或要求补偿。所有的费用应由卖方承担。
③ Acceptance tests will be carried out and，unless otherwise agreed，will be made at the Buyer's works and during normal working hours. If the technical requirements of the tests are not specified in the Contract, the tests will be carried out in accordance with the general practice obtaining in the appropriate branch of the industry in the Country where the Plant is manufactured.
除另有约定外，验收测试应在买方工厂并在正常工作时间内进行。如果合同中没有规定测试的技术条件，测试应按设备制造所在国相应的工业部门所要求的通常惯例进行。

限制性定语从句的翻译方法，除以上最基本的合译法外，有时还可采用分译的方法处理。例如：
④ The Seller ensures that all the equipment listed in Appendix one to the Contract are brand-new products whose performance shall be in conformity with the Contract and which are manufactured according to current Chinese National Standards or Manufacturers Standard.
卖方保证本合同附件一所列全部设备都是新产品，是根据现行的中国国家标准或生产标准制造的，其性能符合合同规定。
⑤ All drawings，designs, specifications and all other technical information made available under this Contact by Party B shall be kept strictly confidential by Party A who shall not sell，transfer or divulge it to anyone without the written consent of Party B，except those of its own employees who will be using it in the manufacture of the product.