In order to improve the frequency stabilization and the anti-interference ability of two-mode power-balance lasers, the asymmetric thermal structure made up of several thermal transfer layers with different heat transfer coefficient is proposed. Through the heat isolation effect of the middle layer in the structure, the laser has asymmetric thermal responses to electric heater control and air interference. So the anti-interference ability of the system is improved by keeping a low speed in air disturbance while keeping a high speed in thermal stabilization. Several experiments were made with two-mode laser to prove the effectiveness of the proposed method. The experimental results indicate that, frequency stability of the two-mode power-balance laser based on asymmetric thermal structure can be locked in 4.1×10-10 in ordinary lab condition, while it becomes 1.9×10-9 where the air velocity is 1m/s.