A simple and environmental friendly oxoacetohydrazide functionalization method is developed to convert the straw cellulose into high performance adsorbents for effective Pb(II) removal. The adsorption experimental results demonstrated that the resultant oxoacetohydrazide-modified cellulose (OMC) possesses a dramatically improved Pb(II) adsorption capacity (82.9 mg/g), which is over six times of that for the unmodified celluloses (13.6 mg/g). The mechanistic studies confirm that the markedly enhanced Pb(II) adsorption capability of OMC can be attributed to the formation of N-Pb-N bonds resulting from the strong chelating interactions of Pb(II) with oxoacetohydrazide. Also, the OMC shows an excellent reusability, capable of retain 95% of its original Pb(II) adsorption capacity after three consecutive adsorption cycles. The findings of this work pave a way to transform the agricultural byproducts into high performance functional materials.