Abstract: Assuming that the soft soil strength obeys the Tresca rule, the influence of the depth of probe embedment on the resistance of T-bar penetration was studied by numerical simulation. It is found that, for the oval, rectangular and rhombus cross section probes with aspect ratio of 0.5,when the depth of the probe centre reaches 4~6 times the probe width, the penetration resistance tends to be fixed. The influence of probe embedment depth on the engineering practice results can be ignored. For oval and rhombus section probes and smooth surface rectangular probes, this value is consistent with the theoretical analysis in infinite soft clay. For the rectangular probe with rough surface, this value is larger than that in infinite soft clay. Analytical solution for penetration resistance of rectangular probe with rough surface is an approximate solution. The results of rectangular cross section probe need to be corrected appropriately.