Two types of molybdenum disulfide (MoS₂) titania nanoheterojunctions with different morphologies were synthesized via two different approaches. They were facile and additive-free hydrothermal processes, which resulted in a high material productivity and controllable morphologies. Both the synthesis and their growth mechanisms are discussed in this paper. The field emission properties of MoS₂ titania nanoheterojunctions were investigated in this research. The experimental data indicated that the MoS₂@TiO₂ heterojunctions had an excellent field emission performance with a turn-on field of 2.2 V μm⁻¹ and threshold field of 3.6 V μm⁻¹ on Si substrate because of the large quantities of sharp edges. Furthermore, because the p–n heterojunctions were formed, the photocatalytic activities of both composites were evaluated by monitoring the photodegradation of methylene blue. The results showed that the TiO₂@MoS₂ heterojunctions had better photocatalytic properties with 90% degradation within 100 minutes. The morphological differences generated from different synthetic approaches made a huge impact on the composites’ properties.