Smart Legal Contract (SLC), as a form of smart contract in accordance with the law, has attracted extensive attention in the recent years. However, there is still a lack of effective technical methods in the conclusion procedure of smart legal contract to make it conform to the current legal regulations, which directly affects the legitimacy of the SLC contract. To address this problem, this paper starts with the relevant legal regulations of contract conclusion, and introduces the idea of Contract Normative Pattern (CNP) that a reusable form, model, or template of contract drafts for conclusion of contract. Based on them, we propose a standardized conclusion procedure of smart contracts, which includes four stages: establishment, deployment, conclusion and deposit, so as to meet the current legal regulations for the conditions of establishment in the written contracts. Meanwhile, a written form of interactive interface is put forward to meet the two stages of “negotiation” and “acceptance” in the contract normative pattern. The former supports the parties to repeatedly negotiate and determine the pending contents in the contract normative pattern, while the latter supports the parties to activate the behavior’s attribute by actively triggering the pre-defined algorithms, e.g., registration and signature. In addition, the syntax of contract conclusion, including parties’ negotiation and acceptance, is introduced into the smart legal contract language, SPESC, in order to meet the “negotiation-acceptance” mechanism in the conclusion procedure. And in this paper we design three blockchain transaction structures to store the interactive data during party registration, signature and clause execution. Finally, taking the sales contract as an example, we analyze the legitimacy of the proposed conclusion scheme from three aspects: negotiation confirmation, acceptance confirmation and deposit legitimacy. The work of this paper will help to provide legal basis for the conclusion procedure of smart legal contract, and promote the construction of legalization on smart contract.