Underwater wet arc welding process was experimentally investigated by using the six types of flux coated electrodes of 3.2 mm diameter and the KR-RA steel plate of 11 mm thickness as base metal. Two types of electrodes were domestic covered arc welding electrode(CR13, CR14) and another two types of wet welding electrodes(UWCS, TN20)were imported goods, and the other two type (UWX1, UWX2) were individually designed flux coated electrodes for experimental welding purpose. Main experimental results are summerized as follows: 1. It is ascertained that individually designed flux coated electrode(UWX1) could be used in practice with KR-RA steel plate for underwater wet arc bead welds. 2. Welding arc can be generated easily and considerably kept in stable using TN20 and UWX1 electrodes. 3. The micro Vickers hardness value and the portion of martensite in the HAZ were increased in all the electrodes by rapid cooling rate, but it is relatively maintain stable for UWCS, TN20 and UWX1 electrodes.