The causes of interstitial pneumonia are either definite or unknown. Most of them are caused by inhalation of plant or animal organic dust in the workplace, including: a. farmers’ lung; b. cotton dust lung, interstitial pneumonia that occurs more often in cotton spinners who inhale cotton dust; c. moldy grass dust lung, caused by inhalation of moldy grass dust with fungi and spores due to contact with damp, moldy hay; d. cane dust lung; e. mushroom lung, mushroom lung is mostly seen in flat mushroom cultivators, this is also This is also caused by inhalation of mushroom spores; six, humidifier and air conditioning caused by; seven, tobacco workers’ lungs. Some inhaled inorganic dust such as talcum powder, these can also lead to interstitial pneumonia. Eight, then there is an unknown cause of direct interstitial pneumonia, slowly leading to interstitial fibrosis of the lung.