In this paper, we develope the auxiliary parameters method to treat thermal-insensitive resonators, derive a new analytic solution applying to any multielement resonator, and analy-ize the stability of resonators、 the thermal-stable charater of output mode and power in detail. Furthermore, by introducing the concept of thermal sensitive degree, we obtain the optimal thermal-insensitive conditions :g1g2=1/2, μ1= 0.