The broadening and shift of the spectral lines of neutral argon in plasma jet at 1 atmospheric pressure are measured. The experimental results are compared with earlier experimental values obtained by other workers, and found good agreement with theoretical values calculated by Griem[1-3]. The temperature of plasma jet are measured by line shift method. The plasma temperature measured by this method are found to be in good agreement within experimental accuracy with those obtained by other spectroscopic methods. From the experimental investigation, it is shown that the shift of spectral line can be used to determine the temperature of plasma jet. The error of this method for the determination of temperature is about 10%.