If you do lose your passport, call your guide or travel advisor for help and notify the local Public Security Bureau (PSB) immediately. The PSB will then issue you a proof of lost passport, with which, you need to go to the nearest embassy or consulate of your own country to apply for a new passport. To have the replacement, you will need to know all the information previously recorded and show identification and proof of citizenship. With the new passport issued, you can get a new Visa in the PSB, so you can go on your trip or re-enter your country. Please note that in some cases, a replacement may take weeks to process, and it may be valid only for a limited time. So take special care of your passport in your journey.