Designing  high-performance Pt-based catalysts with low catalysts cost is still a  great challenge. Here, we demonstrate a facile electrolysis-solvothermal  technique for making Pt and carbon quantum dots coloaded multiwall carbon nanotube (Pt-CQDs/MWCNT) catalyst with the assistant of electric field.  Despite of the ultralow Pt amount (0.81 wt%) for the optimized  Pt-CQDs/MWCNT catalyst, it exhibits ultrahigh electroactivity and  durability toward hydrogen evolution reaction (HER) and ethanol  oxidation reaction (EOR). The mass activities of the catalyst for HER  and EOR can be achieved to 4889.7 mA/mg (-40 mV) and 4917 mA mg⁻¹_Pt  (forward peak), which are 8.1 times and 5.6 times more active than  those of commercial Pt/C respectively. The characterization results  reveal that Pt nanpparticles (Pt NPs) with intrinsic structure play the  key role in excellent catalytic performance for HER and EOR. CQDs not  only support abundant anchoring points for fixation and dispersion of Pt  NPs, but also construct 3D conductive network with MWCNT supporter for  improving the catalytic performance.