[Background] Gold nanoparticles (AuNPs) have various applications in optics, electronics, biomedicines and catalysis due to their high stability, oxidation resistance and biocompatibility. The current research on microbial synthesis of gold nanoparticles is less. [Objective] We performed the intracellular biosynthesis of AuNPs with the biomass of Trichoderma viride. The effects of the biomass addition, initial gold ions concentration and solution pH were also evaluated. [Methods] We performed the intracellular biosynthesis of AuNPs using biomass of Trichoderma viride (GIM3.141). By visual method, ultraviolet visible (UV-vis) spectrophotometer and X-ray diffraction (XRD) and transmission electron microscopy (TEM) and other means to analyze the characteristics of the synthesis of AuNPs. The possibility of biosynthesis of AuNPs was discussed. The effect of reaction conditions on the characterizations of the AuNPs was also evaluated. [Results] The particle size decreased with the increase of biomass addition and solution pH, and increased with the increase of initial gold ions concentration. Reaction conditions such as biomass addition, solution pH and initial gold ions concentrations exhibited great effect on the AuNPs location and size distribution. [Conclusion] On exposing the biomass of Trichoderma viride to aqueous solution of HAuCl4, AuNPs with various shapes including pseudo-spherical, triangular, quadrilateral, and hexagonal ranging from several nanometers to more than 300 nm were produced. For large scale, low cost, clean biosynthesis nanoparticles process provides the species resources.