Dual-frequency laser interferometers are widely used in the field of nanometer measurement. Particular usage context, reducing the errors in a measurement system and improving the measurement accuracy of the system becomes increasingly important. Accordingly, a method is proposed herein to use the vibration modal nodes in the measurement environment to reduce environmental vibrations and improve the measurement accuracy of a dual-frequency laser interferometer. First, the feasibility of the scheme is analyzed from a theoretical perspective, and the experimental measurement system is built based on this theory. Then, the node position in the measurement system is found by using an acceleration sensor. Finally, the measurement repeatability of the dual-frequency laser interferometer in the modal node position and other non-modal node positions are tested. Experimental results show that when there is an external vibration source, the measurement repeatability of the proposed method in the non-modal node position is ±9 nm, and that of the modal node position is ±4 nm. Thus, the measurement accuracy of the dual-frequency laser interferometer in the node position is 125% higher than that in the non-modal node position, which confirms the effectiveness of this method.