Abstract: This paper studies the effects of welding heat,welding press,subsequent heat treatment and cool heat recycles on the phase transformation temperature of the TiNi shape memory alloys welded joints by using differential scanning calorimetry (DSC) and X-ray diffraction.It can be conduded that.both welding heat and welding press has no great effect on the phase transformation temperatures,and the range between A_s and A_f varies little with changed welding heat and press; subsequent heat treatment has a certain effect on it and the values of A_s and A_f raise with heat treatment time in creasing; while cool-heat recycles have a great effect on phase transformation temperature and its process.A_s a result,it is necessary to carry out heat cycles process after welding.