It is unclear how VvLaeA functions in regulating the growth and development of Volvariella volvacea (Bull. ex. Fr.) Sing.. Firstly, bioinformatics analysis of VvLaeA was carried out in this study. Subsequently, the Vvgpd promoter and the open reading frame (ORF) fragment of VvlaeA were amplified and fused by polymerase chain reaction (PCR). The fusion fragment was cloned into the pK2 (bar) plasmid. The recombinant construct pK2(bar)-OEVvlaeA was transfected into Beauveria bassiana by Agrobacterium tumefaciens-mediated transformation. Finally, the growth and development of the transformants were examined. The results showed that VvLaeA shared a low homology with similar proteins in other fungi. Compared with the wild type, the colony diameter of the transformant was significantly increased. However, the pigment deposition, conidial yields and germination rates were significantly decreased. The overexpression strains were more sensitive to stresses than that of the wild type. Further studies showed the conidial cell wall properties of the transformants were altered, and the expressions of genes related to the conidial development were significantly down-regulated. Collectively, VvLaeA increased the growth rate of B. bassiana strains and negatively regulated the pigmentation and conidial development, which shed a light for the functional identification of straw mushroom genes.