The invention relates to immobilized lysine decarboxylase, a preparation thereof, a 1, 5-pentane diamine preparation method and the prepared 1, 5-pentane diamine. The invention specifically relates toimmobilized lysine decarboxylase comprising an aldehyde group-modified polymer carrier and lysine decarboxylase, and a method for preparing immobilized lysine decarboxylase by the aldehyde group-modified polymer carrier; a method for preparing 1, 5-pentane diamine by the immobilized lysine decarboxylase, and the prepared 1, 5-pentane diamine thereof. The immobilization method has high enzyme immobilization efficiency and good stability in use, improves the use efficiency of enzyme, solves the problem of poor use stability of free lysine decarboxylase (cells) in traditional processes, greatlyreduces the use cost of the carrier and the biological production cost of 1, 5-pentanediamine, simplifies the separation step of 1, 5-pentane diamine solution and enzyme, increases the degree of automation of the production of 1, 5-pentane diamine, and promotes the process of industrialization of biological production of 1, 5-pentanediamine.