Based on the “TN concentration threshold-control point liquid level/TN concentration flux” urban rainwater storage method in Dianchi sewage interception trunk canal, this paper investigates the effects of three typical rainfall parameters on the retention of typical pollutants in urban runoff in Dianchi sewage interception trunk canal. The response surface method of Box-Benhnken was used to analyze the effects on the retention of four typical pollutants in urban runoff with three factors and three levels. The results showed that: three typical rainfall parameters have significant linear, square and bifactor interactions on the rainwater runoff collection rate, but only have significant linear on the four typical pollutants collection rate. The mathematical models of three typical rainfall parameters, rainwater collection rate and pollutant collection rate were established to provide reference for efficient management of storm flood in trunk canals.