The work aims to prepare WC particles-reinforced Fe-based wearproof cladding layer on the surface of 45# steel by plasma spray welding provided that back powder-feeding mode was improved. The cladding layer was prepared by plasma spray welding machine and improved back powder-feeding device. Test analysis methods including optical microscope (OM), scanning electronmicroscopy (SEM)，X-ray diffractometer (XRD) and energy dispersive spectrometer (EDS) were used to study microstructure, phase composition and chemical compositions of the cladding layer. Since the distribution of WC particles was mainly determined by back powder-feeding voltage and powder-feeding mode, the distribution of WC particles and utilization ratio of WC powder could be improved by adjusting the powder-feeding voltage and improving back powder-feeding mode. Meanwhile, compared with spherical cast WC and polygonal crystal WC, utilization ratio of the former powder was increased obviously, WC particles were distributed more uniformly and average Vickers hardness of the cladding layer reached over 1500HV10, higher than the latter. Fishbone-like ledeburite structure and a mass of carbides were detected in the cladding layer subject to back-feeding spherical cast WC process. The improved back powder-feeding mode possesses the advantages of synchronous powder feeding and back feeding, providing uniform distribution of WC particles and retaining the original form without significant dissolution. Better cladding effects are made at powder-feeding voltage of 10 V. Spherical cast WC- reinforced cladding layer presents better performance than that of polygonal crystal WC.