Built up box section is a doubly symmetrical section in which two C-channel connected at the flange using self-drilling screw. They are generally used in the construction industry to obtain higher rigidity, when a single section is not sufficient. Despite being widely used in the construction industry, there are limited studies on built-up box section. Moreover, the current design code does not provide clear design guideline for the calculation of built-up box section. Therefore, research on the built-up box section is important. This paper presents a finite element model to predict the compressive strength and simulate the behavior of cold-formed steel built-up box section. The finite element model was developed using ABAQUS CAE/6.14. Comparison of the finite element and experimental results showed good correlation. The model well predicted the behavior of the built-up box column.