Objective: To investigate the biology of the increase of nerve growth factor expression in human dental pulp cells during pulp inflammation. Methods: Immunohistochemistry was separately conducted for nerve growth factor at 6 hours, 12 hours, 24 hours, 48 hours, and 72 hours following 30 µg/mL interleukin-1ß (IL-1ß) action on human dental pulp cells. Results: Nerve growth factor expression increased significantly at 12 hours, 24 hours, and 48 hours after IL-1ß addition. Conclusion: Inflammatory factor IL-1ß induces nerve growth factor expression in human dental pulp cells at the molecular level and is involved in the dental pulp inflammatory process.