not get the sound when record the movie? matinee-UE4

It will not capture audio.

My workaround is to seperately capture the audio using Audacity. Then I use Hitfilm Express to add it back onto the cinematic.

Both Audacity and Hitfilm are available for free.

thank you for the knowledge you give me, I really hope you give me the video link of the tutorial?

I know of no existing tutorial unfortunately.

Google search how to record the Stereo-Mix from your soundcard. This step depends on which operating system you use.

Simply import the video into Hitfilm, Then drag in the new audio track and line it up against the video. Export as a new movie.