I also don't understand. Of course if you get a new passport which I'm about to do, you have to register that with the police station. They need to scan it into their computers and also need to have a copy of it. I thought that the computers at the PSB visa place are linked to are central place where they can check your current passport image regardless of which precinct.

I think what he meant was the he got a new passport from his embassy.

Once the new passport is issued you have ten days (or ten days after you come back to China with a new passport) to start the process of moving the visa/Residence permit from the old cancelled passport to the new one.

Depending on what paperwork you are on you need to start the process with your school or Foreign Experts Department or Foreign Affairs Dept.

I didn't want to make a new thread, but just to warn the long timers. They are stopping all electric bikes on dianchi and guangfu to check registration and passports on ebikes and regular bicycles. No matter what you'll have to pay 20 yuan. It happened to me at 2 different check points today. It's not real police, just traffic police so get their id number and report them if you did not break any laws.

This thread seems to now have several subjects.

Before I leave the country, I let the 派出所 know, and when I return, I go there and give them a copy of my new visa stamp.

The way they explained it was that this keeps them from thinking I've gone for good and closing out my file, then having to open a new one when I show up a week or so later saying, "Oh, I just went to Hong Kong for a few days."

That's my understanding too. Hell, not even they know what the rules are from precinct to precinct.

@HFCAMPO, to attempt to answer your Q, if I understand you correctly.
When you go to the local police to register your residence (with rental agreement etc.) I am pretty sure that they also record your passport number, and visa/RP number.
A new passport and visa/RP would have new numbers, and the police records would not be correct any longer. They would want to have the correct passport and visa/RP numbers on their records.

That's my understanding @TigerTiger.

Every time I go to the 派出所 it's like re-inventing the wheel. They don't deal with many foreigners where I live and it's always an adventure.

Once I was told, "The lady who knows about that is off today. Could you come back tomorrow?"

A Chinese friend who is in the know on such matters told me that part of the problem is that it's policy to rotate clerical staff city wide to keep them from becoming too intrenched at one location. PSB management feels it reduces the chance of malfeasance and graft.

Again, I dont understand.

When I return, I go there and give them a copy of my new visa stamp.
The way they explained it was that this keeps them from thinking I've gone for good and closing out my file, then having to open a new one when I show up.

So how do they know I left? Why would they close my file? Unless they are connected to the mainframe and know that I left the country.

I am more confused now.

They would know you left because they scan your passport on the way out. I assume the immigration department and the PSB share data in China to keep track of how many foreigners are in China and which ports they enter/exit.