In this paper, a pseudonoise (PN) coded ultrasonic holographic imaging system design is studied with computer simulation. A system utilizing PN coded phase‐modulated ultrasonic signals is capable of yielding both high lateral and high range resolution. It is found that the time for data acquisition and image reconstruction is much less than that required for some comparable methods. The PN coded imaging system also has excellent noise immunity, and this is of great practical importance. Some results for a simulated three‐dimensional imaging geometry are shown to demonstrate the characteristics of PN coded ultrasound systems.