Objective In response to the problem of excessive divergence angle of the ultra-thermal electron beam and insufficient brightness of the generated X-ray source in laser-irradiated planar targets a high-power picosecond laser was proposed to irradiate the microwire targets and the effects of electron recirculation on the characteristics of ultra-thermal electron beam and X-ray source were studied. Methods The experiment was carried out on the XGIII laser device. The molybdenum with a diameter of 10 μm and gold microwire targets were used as X-ray sources. A pinhole camera was used to measure the X-ray focal spot in the direction of laser reflection and an electron magnetic spectrometer was arranged in the normal direction of the target to measure the ultra-thermal electron energy spectrum of the escaped hot electron from the target. Results The minimum size of the X-ray focal spot obtained by the pinhole camera reached 10 μm which was equivalent to the diameter of the wire target. The ultra-thermal electron energy spectrum results showed that the maximum temperatures in the self-sustaining independent molybdenum wire and gold wire were 863 keV and 816 keV respectively which were higher compared with the corresponding temperatures and quantities of ultra-thermal electrons in wire targets with CH substrates. Conclusion The experimental results show that removing the low-density substrate of the support wire target is an effective way to accelerate the electron recirculate effect. In this way the intensity and concentration of the ultra-thermal electron beam can be improved which enhances the X-ray bremsstrahlung radiant intensity thus obtaining micro-focus and high-brightness X-ray sources.