what is the result will happen when I misconnect 7.5v power to output of opa333

Damage is definitely possible but probably unlikely if the duration of the 7.5V supply was relatively short. such as a few minutes. Some of the possible damage conditions would depend on the behavior of the 5V supply during this abuse. If the 5V supply can be "pulled up" by application of a 7.5V supply.

If this is a critical circuit, I recommend replacing the IC. 

Regards, Bruce.

Dear Bruce

thanks for your reply, do you have any advice for another IC?

How about placing a 5v TVS beside the output of opa333

Do you mean that this condition occurs repeatedly? I don't recommend that the output of any op amp be driven beyond its power supply voltage.

If you can explain what causes this condition I may be able to suggest a possible solution or protection. Please provide a schematic showing how this condition occurs. Include information on the impedance of the voltage that creates this condition.

Regards, Bruce.

Dear  Bruce Trump 

This condition will occur only when  the misoperation. I hope the misoperation will not damage to my equipment. The following picture is my diagram, vcc_IN is between 6v and 15v, VACC_X, VACC_Y and VACC_Z is the output of opa333. Vcc_IN may be connected to  VACC_X, VACC_Y and VACC_Z when the misoperation.

best regards

linjie pan