The existence condition for some types of integrating factor

In the problem of solving ordinary differential equation,using integrating factor is a useful method.But texts in ordinary differential equation only give some so simple equation that it can be solved by using integrating factor.This article will give two types of integrating factor:u(x~αy~β),u(ax~m+by~n),obtain the existence conditions,and apply these results for solving more complicated ordinary equation whose results are more general than those in the texts.