A field experiment was conducted in Al-Raid Experimental station, Ministry of Resources, 20 km west of Baghdad, during autumn season 2008, in silt clay loam soil classified at typic torriflvent, to study the effect of water irrigation quality, soil mulching on the moisture and salt distribution and cauliflower yield under drip irrigation system. The Experimental design was Factorial Experiment with RCBD in three replicates. The study includes two factors: 1- Water quality, which includes three factors: a- Irrigation with river water (WR) ( 1.1 ds. m-1). b- Irrigation with saline water (WS) ( 4.5 ds. m-1). c- Alternate irrigation (WA).2- Soil mulching includes two factors: a- Soil mulching with black polyethylene (M). b- With out mulching (W). The results can be summarized as follows: It was notice that the moisture content increase at the emitter sources and decreased away from the source vertically and horizontally for all treatment at the end of the irrigation, the wetting front increase away from the emitter source with increased the depth of the soil. Also the wetting front movement increase vertically and horizontally when the soil covered with black polyethylene, also the leaching requirement caused increase the moisture content for irrigation treatment with saline water. Saline soil increase vertically and horizontally away from the emitter source, and moved with wetting front away from the emitter source when the irrigation depth increased. The higher salt accumulation was found at wetting front vertically and horizontally, and the salt was distributed increasingly with the depth in soil mulching treatment, also it was found that the salinity of salt water treatment was greater than the alternate and river water treatments respectively. Irrigation treatments and mulching were effect on the yield, The higher yield was 42.95 ton / hector when irrigated with river water and mulching compare with low yield 22.03 ton/ hector when irrigated with saline water and with out mulching.