Abstract: The cellular and biochemical effects on bronchoalveolar lavage fluids (BALF) of the rats after inhalation of TPA dust were analysed.The average geometric concentrations of TPA dust in experimental groups were 8.93mg/m³, 274.45mg/m³ and 618.12mg/m³ respectively. It was discovered that pulmonary alveoar macrophages (PAMs) in BALF of the rats exposed to TPA dust at the middle and high concentrations were significantly decreased while acid phosphatase (ACP) was significantly increased, and NAG in the high concentration group was significantly increased as compared with those in the control. The results showed that PAMs of the rats could be injured. The change inthe protein content In BALF suggested that immlune process might be involved in the lung damage induced by TPA inhalation.