We present the results of hydrodynamical model calculations of the barred galaxy NGC 5850 and compare to HI observations. The models assume a mass distribution for the galaxy which was obtained from photometrical I band observations. A pure bar perturbation model reproduces the HI observations in the inner 80'' of the galaxy. The reproduced morphological features are: the central gas concentration, the hole of gas in the bar region and the ring of HI located at the end of the bar. The spiral arms are not reproduced. The best model has the co-rotation located at 90'' and the mass of the bulge, bar, disk and halo are respectively: 4.7*E9 Msun, 4.6*E9 Msun, 4.9*E10 Msun and 6.93*E10 Msun.