Abstract: To analogize the blackbody radiation formula，the time course line distribution or the change regulation along the way of the reciprocal of pollutant concentration in one-dimensional flow field can all be described with Plank' s distribution formula of space-time transition of the pollutant concentration． Combined with the measured monitoring data of pollutant in river water，the parameters in the formula were optimized by using immune evolutionary algorithm ( IEA) ． Optimized Plank's formula of space-time transition of pollutant concentration in one-dimensional flow field can be obtained． Cases analysis showed that the formula was clear in meaning，simple in form，easy to calculation and had the feature with fewer parameters．