Abstract: In this papper,a general approach estimation latency distribution of chronic diseases using data collected by the time-windows form a case-control study,is proposed based on the theory for risk analysis of fuzzy states.Making use of a forward-analysis and backward-synthesis strategy and excess exposure fraction,thisapproach can simultaneously accomplish multivariate logistic regression analysis and estimation of latency distribution.The latent period is resoved into the accumulative period of effective exposures and the sojourn period of predisease states.It gives a theoretical guide and interpretation to primary and secondary prevention of chronic diseases.