Abstract: Smart legal contract (SLC), as a form of smart contract in accordance with the law, has attracted extensive attention in recent years. However, the conclusion procedure of an SLC still lacks effective technical methods to make it conform to the current legal regulations, which directly affects the legitimacy of the SLC contract. Therefore, this paper starts with the relevant legal regulations of contract conclusion and introduces the idea of contract normative pattern (CNP), which is a reusable form, model, or template for contract conclusion. Based on these regulations, we propose a standardized conclusion procedure of smart legal contracts. This procedure includes four stages: establishment, deployment, conclusion, and deposit to meet the current legal regulations for the conditions of establishment in the written contracts. Meanwhile, a written form of interactive interface is proposed to satisfy the two stages of “negotiation” and “acceptance” in the CNP. The negotiation stage supports the parties to repeatedly negotiate and determine the pending contents in the CNP, and the acceptance stage is to activate the behavioral attribute by actively triggering predefined algorithms, such as registration and signature. In addition, the syntax of contract conclusion, including parties’ negotiation and acceptance, is introduced in the SLC language, SPESC, to adhere to the “negotiation-acceptance” mechanism in the conclusion procedure. In this paper, we design three blockchain’s transaction structures to store interactive data during party registration, signature, and clause execution. Finally, considering the sales contract as an example, we analyze the legitimacy of the proposed conclusion scheme based on three aspects: negotiation confirmation, acceptance confirmation, and deposit legitimacy. This paper will provide a legal basis for the conclusion procedure of an SLC and promote better achievement of legalization of a smart contract.