There are many property rules.

If the property right of your yard is on the property right certificate, then the property staff's practice is illegal entry. You can negotiate with the property first. If not, you can call 1 10 to call the police. If not, you can record it and sue.

If the property right of your yard is not on the property right certificate, but when you buy a house, the seller tells you that you can enclose the place in front of the door for your own use, then you belong to an illegal building. It is good that the property is not allowed to be demolished. Don't be serious with him.