The air gap discharge is the main pattern of partial discharge of transformer insulation paper. Studying the correlation of partial discharge and gas production rules is important to diagnose early generation and development of the paper oil insulation. The paper design a simulation experiment system of transformer partial discharge in laboratory, and study gas discharge and development characteristics under the condition of 60 ℃ and the way of increasing voltage method. By major-content method, six major factors are selected from 29 statistic operators. And the six major factors are independent with each other. Results show that there is correlation between six kinds of gas and six major factors by correlation and regression method, and multivariable linear regression model of six kinds of gas and six major factors is presented. The above results provide a new idea for further discussing the relationship between early development of transformer partial discharge and the rule of gas production in oil.