We present a precise passive frequency difference stabilization scheme for the Y-shaped cavity dual-frequency laser. A two-stage thermostat and a precision steady current circuit were designed to stabilize the temperature and discharge current of the laser. The laser relative frequency difference drift rate is stabilized within 0.011% at room temperature. The result shows an improvement of two orders of magnitude over the stress-induced birefringence closed-loop control method. This scheme will further improve the accuracy of acceleration and precision force measurement. Moreover, the scheme shows the great potential in industrial applications because of the low cost and good environmental adaptability. In addition to the temperature change, we found that the mode repulsion also affects the stability of the frequency difference.