How did the gradual color change of the sky come out in the photographic landscape blockbuster? I want to solve this problem. ...

To be sure, this is definitely not the effect of direct shooting. There are two ways. One is to add a gradient mirror in the early stage, which is gradient blue. The other is the effect of using gradient blue filter in the later PS, combined with dimming angle, adjusting hue and saturation. How to adjust it specifically? Try more in PS. In short, these two methods can make you get such an effect map.

In any case, the early shooting is also very important, especially in this scene, you must use a slow shutter and a large aperture, use a tripod, use a countdown selfie or a remote control when shooting, and you can't press the shutter directly, otherwise the slight vibration will destroy the beauty and clarity of the picture. And it is best to use RAW format for post-processing. It's just that taking pictures of this kind of scenery in RAW format will be very big. Generally, it is common to take more than 20MB, and 50MB is common. Therefore, I suggest that you prepare an SD card above 32GB. Such a beautiful picture usually needs a professional SLR to shoot.