To disable the "Si Yuan Code"payment function, please follow the steps:

"My SJTU"App -> Si Yuan Code -> "... in the upper right corner -> Shut off the payment function.

After that, the Si Yuan Code page will display a prompt message: "Payment function has not been enabled yet. Please click to enable." At this point, Si Yuan Code cannot be used for payments. If you need to re-enable the payment function, simply click the prompt button mentioned above to re-enable it.