Light-emitting device and manufacturing method thereof, vehicle tail lamp and vehicle

A light-emitting device, a method of manufacturing the same, a taillight, and a vehicle, the light-emitting device comprising: at least one light-emitting element (10) located on one side of a back plate (BP), each light-emitting element (10) emitting a first light having a wavelength of 500 nm to 580 nm; the wavelength conversion layer (20) is located on the side, away from the back plate (BP), of the at least one light-emitting element (10) and is configured to emit second light different from the first light in color under excitation of the first light; and a first optical structure (40) located on a side of the wavelength conversion layer (20) away from the backplane (BP), comprising one or more optical elements (41), each optical element (41) being configured to focus the second light in a direction perpendicular to the backplane (BP).