合同的订立（conclude a contract）是指缔约当事人相互为意思表示并达成合意而成立了合同。

合同的订立由“订”和“立”两个阶段组成。“订”强调缔约的行为和过程为是缔约各方接触、洽商过程，包括缔约各方的接触、洽商并最终达成协议前的整个讨价还价过程。

“立”强调缔约的结果,指的是双方合意的达成，即双方当事人就合同条款至少是合同的主要条款已经形成一致意见，各方当事人享有的权利和承担的义务得以确定。

合同订立的基本原则如下：

1、平等原则；

2、公平原则；

3、自愿原则；

4、诚实信用原则；

5、不得损害社会公共利益原则。

相关双语法规：

《合同法》第三条：

合同当事人的法律地位平等，一方不得将自己的意志强加给另一方。

Contracting parties shall have equal legal status, and no party may impose its will on the other party.

《合同法》第四条：

当事人依法享有自愿订立合同的权利，任何单位和个人不得非法干预。

The parties have the right to lawfully enter into a contract of their own free will in accordance with the law, and no unit or individual may illegally interfere therewith.

《合同法》第五条：

当事人应当遵循公平原则确定各方的权利和义务。

Article 5 The parties shall adhere to the principle of fairness in deciding their respective rights and obligations.

《合同法》第六条：

当事人行使权利、履行义务应当遵循诚实信用原则。

The parties shall observe the principle of honesty and good faith in exercising their rights and performing their obligations.

《合同法》第七条：

当事人订立、履行合同，应当遵守法律、行政法规，尊重社会公德，不得扰乱社会经济秩序，损害社会公共利益。

In concluding and performing a contract, the parties shall comply with the laws and administrative regulations, respect social ethics, and shall not disrupt the social and economic order or impair the public interests.

《合同法》第八条：

依法成立的合同，对当事人具有法律约束力。当事人应当按照约定履行自己的义务，不得擅自变更或者解除合同。依法成立的合同，受法律保护。

A lawfully established contract shall be legally binding on the parties thereto, each of whom shall perform its own obligations in accordance with the terms of the contract, and no party shall unilaterally modify or terminate the contract. The contract established according to law is protected by law.

参考双语例句：

The approach taken with regard to suspension — that is, to allow the procuring entity to decide on the matter — is designed to strike a balance between the right of the supplier or contractor to have a challenge reviewed and the need of the procuring entity to conclude a contract in an economic and efficient way, without undue disruption and delay of the procurement process.

对暂停采取这种做法—即允许采购实体就此事作出决定--意在实现两方面的平衡，一方面是供应商或承包商要求对一项质疑进行审查的权利，另一方面是采购实体经济、高效地订立合同，不使采购程序受到不当干扰和延误的需要。

The Provincial High Court considered that, although the judgement appealed against also cited Spanish case law in relation to article 1124 of the Civil Code (Discharge by breach), such case law was along the same lines as article 25 of CISG, which provided that the buyer might declare the contract avoided where the breach was serious and fundamental, without needing to adduce the failure to perform secondary or complementary actions that, not being of vital importance, had not prevented the creditor from obtaining the financial result that had prompted it to conclude the contract.

省高等法院认为，尽管上诉所针对的判决也援引了与《民法》第1124条（因违约而解除合同）有关的西班牙判例法，但这种判例法与《销售公约》第25条相一致，其中规定，如果发生严重和根本违反合同，买方可宣布合同无效，而无需引证未能实施后续或补充行为，因为这些行为不是至关重要的，并未妨碍债权人获得促使其缔结合同的财务结果。