这是我再国外论坛上找到的一个方法，添加个WifiMaxPeers项目即可。

If you add a Dword value named WifiMaxPeers to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\icssvc\Settings

it will change the upper limit in Mobile Hotspot, e.g. I changed it to decimal 10, and the Mobile Hotspot control panel showed "Devices connected: 0 of 10".

I have tested this with 10 connected clients concurrently.

I strongly suggest making the change with Mobile Hotspot turned off and rebooting for the changes to take effect.

The maximum value of this key appears to be decimal 128. Larger values prevent Mobile Hotspot from starting.