The classical optical theory was introduced to calculate the interaction between laser beam and powder stream, on the basis of which the effect of powder feeding rate on the laser intensity and temperature of the particles at different sites on the surface of the workpiece was investigated. It is shown that the peak values of both laser intensity and particle temperature decrease with increasing the powder feeding rate. And simultaneously, the laser intensity distribution and the temperature of the particles at different sites on the surface of the workpiece tend to be even. It is suggested that such results should be considered in model of laser cladding due to their subtle effects on the dynamic processes in laser molten pool.