In the west the form of dress prescribed for formal events after noon is traditionally Evening wear. In other words the Tuxedo. The military equivalent for the west is the “Mess Dress”, “Dinner dress” or “Full dress uniform” basically a military tuxedo.
I know that the PRC adopted the “Mao Suit”; Under well Mao. As the equivalent to the western tuxedo as formal evening wear for diplomatic functions. Does the PLA have Formal uniform equivalent mess or dinner dress?
Is it a Mao suit done up with military paraphernalia? Or do they just ritz up the service uniform?
No, the "Mao Suit" is actually known as "Zhongshan Suit" in Chinese, named after Sun Zhongshan, aka Sun Yatsen. As far as I know, there are no formal prescriptions of evening wear in China. Both Western and Zhongshan suits are acceptable as formal wear for men.
Also AFAIK, the formal wear for Chinese military personnel are these:
I'm not 100% certain, but I think the white uniform is for the navy and the green uniform for the army.