In order to investigate the influence of laser power, scanning speed and powder feeding rate on the properties of Fe-based alloy powder cladding on the surface of 45 steel, single-pass forming test of laser cladding was carried out using orthogonal test scheme. The ratio of width to height, dilution rate and hardness of the cladding layer were used as the evaluation indexes to judge the performance and quality of the cladding layer, The influence of each cladding process parameter was judged by range analysis, and the best combination of single cladding process parameters was obtained based on multi-objective optimization method of genetic algorithm. Results show that the powder feeding rate is the main factor affecting the hardness of cladding layer, and the laser power is the second one. Scanning speed is the main factor affecting the height and width of cladding layer. The feeding rate is the main factor affecting the dilution rate. The optimal combination of process parameters is obtained, i.e., laser power 2 056 W, scanning speed 8.75 mm/s, and powder feeding rate 2.198 g/min, which provides guidance for the selection of process parameters of laser cladding iron-based powder for 45 steel.