In order to express the distribution of the laser energy in the processing of powder feeding laser cladding, the concept of the laser effective energy utilization rate β was formulated. The equation expressing the relationship between the laser effective energy utilization rate β and the parameters of the laser coated layer and the processing parameters was derived based on the energy equilibrium and the interaction between the laser beam and the powder particles and the substrate material. The experimental method for determining the laser effective energy utilization in laser coating process by powder feeding method was designed. By varying the powder feeding rate and the scanning speed Vs under the definite laser power P and the beam spot dimensions, the coatings with different thickness were obtained. The factors affacting the laser effective energy utilization were studied carefully. When the powder feeding rate and the scanning speed Vs increase, the laser effective energy utilization becomes larger, the energy absorbed by powder material becomes larger also. A reasonable explanation on why a maximum is observed in the relationship between the scanning speeding and the laser effective heat utilization is presented. It is the theoretical foundation for further study on the relationship between the processing results and the processing parameters quantificationally.