A kind of facultative methanotroph strain was screened from 10-year aged-refuse. It was able to grow not only on methane but also on multi-carbon substrates，such as glucose，fructose and starch. According to the biochemical characteristics and the 16S rDNA identification results，the facultative methanotroph strain belonged to Chryseobacterium sp. and was named as JT03(CCTCC NO.M2010100).Based on counterbalanced growth model and Monod equation，model of nutrient uptake kinetics of Chryseobacterium sp.JT03 was derived to evaluate its affinity to methane oxidation. Under the condition of the low-density culture（OD=0.362±0.012），consumption rates of methane were studied with different initial contents of methane in the range of 1%—40%(vol)，consumption rates were fitted and the coefficients of correlation were in the range of 0.967—0.998. Hence，it fitted the Monod equation well according to the plot of consumption rates of methane with different initial concentrations. Semi-saturation constant KS was calculated by linear fitting and its value was 7.097 mmol