Abstract: In order to obtain 1.444μm Nd:YAG pulsed laser,the theoretical model of the 1.444μm Nd:YAG pulsed laser system was build up according to the rate equation theory and the laser producing condition of other spectrum with high cross section was analyzed.The output of double wavelength laser of 1.444μm and 1.064μm was calculated in pulsed pump condition.The numerical results indicated that the low 1.064μm laser emission had not obvious effecton the 1.444μm laser output.The amplified spontaneous emission(ASE) effect on the laser output was calculated by one-dimension numerical model.The ASE effect was less than 2% and might be neglected in the ideal condition that there was no reflection on the crystal surface.