Abstract: In order to understand the behavior and interaction of main sugars and amino acids in tobacco during cigarette combustion,the behaviors of glucose,fructose,sucrose and proline pyrolyzed independently or collectively were investigated by Py-GC/MS,the behaviors of co-pyrolysis and independent pyrolysis were analyzed and compared.The results showed that:1) The co-pyrolysis of glucose,fructose and sucrose with proline impacted obvious influences on the formation of volatile compounds comparing with independent pyrolysis.When the ratio of sugars to proline was 5:1,5-hydroxymethyl furfural formed in the process of co-pyrolysis were about 3.4%,6.0% and 20.3% of that formed in the independent pyrolysis of glucose,fructose and sucrose,respectively;furfurals formed were about 5.9%,2.0% and 6.3%,and levoglucosans were about 1.0%,27.1% and 8.7%,respectively.When the ratio of sugars to proline was 10:1,5-hydroxymethyl furfurals formed in co-pyrolysis were about 35.5%,30.0% and 81.3% of that formed in independent pyrolysis of glucose,fructose and sucrose,respectively;furfurals formed were about 29.9%,11.3% and 22.5%,and levoglucosan were about 11.5%,90.6% and 26.9%,respectively.2) The composition of sugar mixture and its ratio to proline significantly affected the formation of pyrolytic products,and the influence raised with the increase of proline content.