Visible near infrared (VNIR) transition-metal dichalcogenides (TMDs) photodetectors have attracted attention due to their unique electronic and optoelectronic properties. Herein, the photodetection performance of a novel MoTe2/ReSe2 van der Waals heterojunction (vdW HJ) diode is studied in the VNIR region. Density functional theory calculations reveal the formation of type-II band alignment, which is beneficial for the design of a MoTe2/ReSe2 HJ diode with better optoelectronic properties. A superb rectification ratio of ≈1 × 104 is obtained via gate engineering, in which the ambipolar nature of MoTe2 enables a transition from p+–i to n–n+ state. In addition, the diode exhibits an excellent figure of merit for photodetection. The excellent diode performance is demonstrated by a high responsivity of 5.6 × 102 A W−1, an excellent detectivity of 8.1 × 1013 jones, and an external quantum efficiency of 9.5 × 102. Moreover, fast rise and decay times of 2 and 4 ms, respectively, are observed under illumination. The significant improvement is attributed to the combination of an intra-TMD band-to-band transition and an inter-TMD charge transfer process in the MoTe2/ReSe2 vdW HJ. This study provides an opportunity for advancing the prospects of TMDs in next generation optoelectronics.