The deep levels of P-HEMT structure grown by MBE have been studied using DLTS technique. DLTS Spectra of samples show that high temperature electron traps, having larger capture cross sections and concentrations, are measured in n-AlGaAs layer of P-HEMT structure. These traps may correlate strongly with oxygen content of n-AIGaAs layer and be responsible for electrical parameters of P-HEMT structure. The experimental results also show that DLTS technique may be a tool of optimisation design of practical devices.