Abstract: The addition reactions between camphene and carboxylic acid catalyzed by p-toluenesulfonic acid in a sealed reacting pot under microwave irradiation were studied. Factors affecting the reaction of camphene with formic acid were discussed in detail. The main products were isobornyl formate, 3-camphanyl formate, camphene hydrate, isoborneol, 3-camphanol, isofenchyl formate,etc. Results showed that the content of isobornyl formate in the reaction mixture reaches 77.2% in addition reaction of camphene 25 mmol with formic acid (53 mmol) catalyzed by p-toluenesulfonic acid 0.20 mmol under microwave irradiation for 40 s (microwave power 700 W). Microwave irradiation could raise the reaction rate greatly. This research provided a new approach for esterification of camphene.