This paper investigates the application of cooling plate in a 4500m3 blast furnace in China. SEM‐EDS and an optical microscope were used to examine the affected area. The results demonstrate that using a cooling plate in a big blast furnace has a positive effect, notably in the belly and bosh areas, where the damage rate is less than 3%. While the cooling plates in the middle shaft are more severely damaged, with a damage rate of up to 55.40%. The majority of the copper cooling plate’s damage is centered in the water channel area, where there are furrows and numerous microcracks on the damaged surface, as well as a tiny quantity of metallurgical slag attached. Cracks form on both the inside and outside of the water channel, and the grains surrounding the cracks rise significantly, which is the primary cause of the cooling plate’s water leaking. The main factor of cooling plate damage in the early stage is wear, and the cracking caused by force in the later stage. The use of a copper cooling plate from the furnace bosh to the lower shaft is preferable to the use of a copper cooling stave.This article is protected by copyright. All rights reserved.