Can I bring my camera into Shanghai's musical Cat in August? SLR camera

you can bring it, but just don't be found.

you can take photos, video or audio, but just don't be found. . .

But the flash should never be used, because it will affect the performance of the actors. . . .

based on the above points. . . . The possibility of SLR being discovered is very high. . . . Although it won't confiscate your tools, it's not impossible to ask you out of the theater or something. Use a film player.