I make it clear, the offical guide about package on MacOS is below:
But it is not clear enough.
First we have to compile the electron project in delphi on Windows with the 'MacOS 64' build option, pas2j will translate the code from pascal to java script, an error message would be shown in console: Build MacOS 64 on Windows is not support, it dose not matter, an output folder 'Build-MacOS64' under the TMSWeb folder will be generated, this is the key point.
Then copy the 'Build-MacOS64' folder to a Mac and run 'npm run builde-mac64' under the folder. The electron-packager can works correct by this way.