Abstract： Objective To study the feasibility of dendrimer-entrapped gold nanoparticles (Au DENPs) as a CT molecular probe. Methods Fifteen concentrations (0.001 to 0.1 mol/L) of gold nanoparticles were entrapped by amine-terminated polyamidoamine dendrimers of generation 5 in experiment groups. Same concentrations of non-ionic iodine contrast agent (Omnipaque) were set as control groups. The CT value of each concentrations of contrast agents in two groups were detected and compared in vitro. Six concentrations (0.006 ～ 0.02 mol/L) of Au DENPs at a dose of 10 μl were injected into the subcutaneous soft tissue of BALB/C mice back according to the experiment in vitro, then the experiment mice were scanned by a micro CT system to evaluate the development effect. Results (1) The CT values of Au DENPs were lower than those of non-ionic iodine contrast agent, when the concentration was 0.01 mol/L or lower in vitro. However, when the concentration exceeded 0.02 mol/L, the CT values of Au DENPs were higher than those of non-ionic iodine contrast agent. (2) Au DENPs at a dose of 10 μl injected into the subcutaneous soft tissue of mice could be detected by microCT, when the concentration of these particles was not less than 0.009 mol/L in vivo. At concentrations less than 0.008 mol/L, Au DENPs were undetectable in vivo. Conclusions Au DENPs show better inherent character for imaging than existing CT contrast agents, which preliminarily qualifies its use as a CT molecular probe.