By calculating the simultaneous dualwavelength threshold condition to supp ress 1064nm strong line,we developed a 1318.8nm /1338nm simultaneous vibrating dual wavelength Nd∶YAG quasi2CW laser. The output power of 101W was obtained at a pump power of 2015W with the total efficiency of 5.01% , the slope efficiency of 7. 05%. The unstability of output power is less than ±5%. The centralwavelengths of laser are 1318. 8nm and 1338. 2nm with the FWHM of 0. 407nm and 0. 376nm, respectively.