The MIKE 21 FM model, developed by the Danish Hydraulic Institute, is a distributed system model that is used in hydrological calculations, water quality simulation, sediment transport calculations, resources and water environment in rivers, estuaries, coastal areas, and seas... This paper is an initial step in setting and establishing a set of model's parameters for simulating contaminant transport at the Dinh Vu coastal area, Hai Phong city under different scenarios. The model was calibrated and validated with the real data at 8 surface water quality monitoring sites at Hai Phong coastal area in 2014 and 2015. The result obtained by MIKE 21 HD for adjusters and good quality with specified Nash are 0.96 and 0.93, respectively. The relatively wrong number of Ecolab parameters are below 20 %.