The aim of this work was to study the physical and chemical changes of cornstalks surface after different treatments targeting at its better application in foam packaging materials. The cornstalks were treated using a variety of processing methods such as diluted acid treatment, hot sodium hydroxide treatment, steam treatment, hydrothermal treatment and microwave treatment, and characterization and morphology analysis were conducted using Fourier transform infrared spectrometer, scanning electron microscope, and contact angle tester. The infrared analysis showed that all the methods could reduce the content of lignin; diluted acid, hot sodium hydroxide and steam treatments reduced the cellulose content; hot sodium hydroxide, steam, hydrothermal and microwave treatments reduced the contents of lipid compounds; all kinds of methods could break the structure of aromatic compounds except hydrothermal treatment, and only hot sodium hydroxide treatment could destroy the Silicon oxygen bond. Scanning electron microscopy showed that high-temperature treatment had relatively good effect on the cornstalk surface. The Contact Angle test revealed that after treatments with sulfuric acid, acetic acid and hot sodium hydroxide, steam, hot water and microwave, the contact angle decreased by 4.58°， 12.5°， 22.5°， 9.8° ，1.4° ，6.85° on average, respectively. In conclusion, The hot sodium hydroxide treatment had the best effect on cornstalks surface, while the treatments with sulfuric acid, acetic acid, steam, hot water and microwave had insignificant effect.