This study investigates the submerged ultra-high pressure jet characteristics of a TSHD by experimental and numerical methods. The results indicate that the dynamic pressure undergoes exponential decay with the increasing jet distance. Moreover, it shows that the numerical results are in good agreement with the experimental ones. On the basis of the results, the study analyzes the jet flow characteristics of the ultra-high pressure jet. In the case of an ultra-high pressure jet, the moving speed does not have a significant change in the flow characteristics. The influence of the velocity field and the value of the velocity obviously increase with the increase in the jet pressure. Therefore, an increase in the jet pressure can improve the flow-field characteristics and the efficiency of the dredging process.