We report on the significant suppression of randomness of the electrically pumped random lasing (RL) from ZnO-based metal-insulator-semiconductor (MIS) structured light-emitting devices (LEDs), by means of adopting the appropriately patterned hydrothermal ZnO films featuring large crystal grains as the light-emitting layer. The hydrothermal ZnO films on silicon substrates, with the crystal grains sized over 500 nm, were firstly patterned into a number of square blocks separated by streets by using laser direct writing photolithography. Based on such patterned ZnO films, the MIS (Au/SiO₂/ZnO) structured LEDs on silicon were prepared. Under the same injection current, the LED with the patterned ZnO film exhibited much fewer RL modes than the counterpart with the non-patterned ZnO film and, moreover, the former exhibited ever-fewer RL modes with the decreasing block size. Besides, the wavelength of the strongest RL modes from the LED with the patterned ZnO film fluctuated in a much narrower range with respect to that from the LED with the non-patterned ZnO film. It is worth mentioning that the LED with the patterned hydrothermal ZnO film can even be pumped into the single-mode RL under the desirable conditions such as low injection current and small patterned blocks. Moreover, the comparative investigation indicated that the LED with the large-grain hydrothermal ZnO film exhibited the smaller RL threshold current than the counterpart with the small-grain sputtered ZnO film, and, the former had fewer RL modes and a higher output lasing power than the latter under the same injection current. As for the physical mechanism underlying the aforementioned results, it is analyzed as follows. Regarding the LED with the patterned ZnO film, on one hand, due to limited numbers of crystal grains and grain boundaries within a single block, the multiple optical scattering is remarkably suppressed. Then, the paths through which the net optical gain and therefore the lasing action can be achieved via the multiple optical scattering are much fewer than those in the case of the non-patterned ZnO film. On the other hand, due to optical gain competition among different RL modes occurring within the limited space of a single block, the RL modes with significant spatial overlap could not lase simultaneously. For the two-fold reasons as mentioned above, the LED exhibits ever-fewer RL modes with decreasing size of blocks. Moreover, the inter-block optical coupling enables the optical gain competition among different RL modes to be more violent within a single block, leading to further reduction of RL modes.