Reactive dyes containing a dichlorotrianinyl dye of high reactivity, a vinyl sulfone dye of medium reactivity, and a monochlorotriazinyl dye and a acryl bromide dye of low reactivity were applied to silk fibers by two step and single step alkali-process with the variation of several dyeing condition factors. The effects of dyeing condition factors taken as variables on the level dyeing were studied and discussed by introducing the levelness parameter L.P.(fixation), defined by L.P.(fixation) =F1/F0, where Fl=fixation during first 10min. of fixation, and F0=maximum fixation. In the two step alkali-process, the concentration of salt(Na2SO4), the amounts of adsorption and fixation and the rate of adsorption at adsorption process had all no relation with the levelness of dyeing, but the rate of adsorption at fixation process exhibited good inter-relation with the levelness. In the single step alkali-process, the rate of adsorption and the rate constant showed good corelation with the levelness, but it was difficult to corelate the diffusion coefficient with the levelness.