The work aims to study the relationship between processing parameters and forming characteristics in laser cladding of Fe-based alloy powder and powder effective utilization rate for the problem that surface geometry of cladding layer is difficult to reach the processing requirements and the utilization rate of powder is lower. Test plan of laser surface cladding was designed and Fe-based alloy powder was used for single track laser cladding on the 45# steel substrate with different processing parameters. The relationship between processing parameters and forming characteristics of each laser cladding test was researched by orthogonal test. With the increase of laser power, clad width, melt pool depth and dilution rate increased, but infiltration angle and aspect ratio of cladding layer decreased. Meanwhile, powder effective utilization increased from 12.9% to 42.6%. With the increase of powder feed rate, clad height increased. However, melt pool depth decreased, and powder effective utilization decreased from 27.9% to 14.7%. With the increase of laser scanning velocity, clad width and clad height deceased, and powder effective utilization increased first and then decreased. Therefore, effective utilization of powder decreases as powder feed rate increases, which increases the cost of laser cladding. However, the proper increase of laser power can not only obtain good cladding layer geometry, but also increase effective utilization of powder. Under the condition of 450 W, 9.6 g/min and 390 mm/min, the powder effective utilization is high and good geometry of cladding layer is obtained. These experiment results provide some references for the application of laser cladding.