The fabrication of MoS2 nanospheres with an average diameter of 100 nm via a surfactant-assisted route was reported, in which an amorphous MoS3 precursor was obtained by the aggregation transformation of surfactant at a low temperature and then transformed to the MoS2 nanospheres with quasi-fullerene structures by thermal decomposition. The final products were characterized by XRD, IR, SEM, and TEM, respectively. The results indicate that the polyethylene glycol (PEG) promotes the formation of nanospheres and has a great effect on the microstructures, resulting in the abnormal expansion of lattice. The possible transformation mechanism of structures has been discussed based on the experimental results.