房屋承租人的优先购买权是指在出租人出售其所租出的房屋时，承租人拥有的同等条件下优先购买的权利。承租人优先购买权的设定，旨在稳定租赁关系，最大限度地发挥房屋作为一种特殊租赁物的价值，同时也是对处于弱势地位的承租人的保护。作为一项重要的权利，其制度设计也几经变更。

本文以《民法典》体系下的优先购买权制度为基础，首先追溯了该权利在我国的发展历史，论述了研究该制度的必要性。在此基础上，本文详细分析了该权利的法律性质，认为承租人优先购买权应当被认定为形成权。通过对《民法典》条文的解释，优先购买权的行使需要具备一个主体要件、四个积极要件、三个消极要件。本文最后结合司法裁判和学理上有争议的要件进行了论述。

The preemption right of the lessee refers to the priority of the lessee to purchase the leased house under the same conditions when the lessor sells it. The tenant's right of first refusal was created to stabilize the lease relationship, maximize the value of the house, and protect the more vulnerable tenant in the transaction. As an important right, its institutional design has changed several times.

This article is based on the institution of preemption under the system of Civil Code. Firstly, it traces back the development history of the right in our country, and discusses the necessity of researching the system. Secondly, the article analyzes the legal nature of the right in detail, and gives an opinion: the lessee's preemptive right should be identified as the right of formation. Then, through the literal interpretation of the provisions of the Civil Code, it can be found that there are one subject element, four positive elements and three negative elements of the right. And then, the paper combines and discusses the disputed elements in combination with the judicial judgment and various theories.