Current seismic design method can hardly be effective to avoid the seismic damage of nonstructural components，which results in a large number of economic losses． In this paper，uncertainties involved in the generation of seismic fragility curves and evaluation of seismic loss ratio were taken into account，where the capacity median， capacity dispersion and damage factors are regarded as basic random variables with different coefficient of variation ( COV) to investigate the influence on the COV of seismic loss ratio of nonstructural components． Furthermore，a probabilistic approach is developed to estimate the seismic loss ratio of nonstructural components based on empirical regression analysis approach． As a result，once the magnitude of seismic response parameters of nonstructural components is determined，the mean value and standard deviation ( STD) of seismic loss ratio of drift-sensitive and acceleration-sensitive nonstructural components can be predicted directly． The conclusion indicates that the dispersion of seismic loss ratio of nonstructural components increases with the rise of inter-storey drift ratio and floor acceleration，but becomes stable in the end． The variation of seismic fragility parameters at life-safety ( LS) ，collapse prevention ( CP) performance level and seismic damage factors affect the variation of seismic loss ratio of nonstructural components significantly． Such observation benefits the estimation of seismic loss ratio of nonstructural components in probability．