To overcome the defects of large error in two-longitudinal-mode wavelengths interferometer for absolute distance measurement, a new kind of multi-wavelength absolute distance interferometer is introduced. A double-mode 633 nm He-Ne laser and a 629 nm He-Ne laser are employed to generate 117 μm synthetic wavelength, with which distance with high precision is measured by using the double heterodyne interferometric technique. The static and dynamic experiments show that due to the shorter synthetic wavelength, the uncertainty can reaches 3.8×10-6L+57 nm and the error is 2 μm within 500 mm. From the uncertainty of synthetic wavelength, the error of the new interferometer is also discussed. The interferometer could measure distance with high precision if coupled with two-longitudinal-mode beat measurement system.