Thanks for all your responses. when I used setupdixxx and createfile, I think I got the handle to the filter. Because as I changed to declare the property item in the automation table in filter descriptor, I can set the property to filter. But in my project, I need to set the property to the pin. I read Directks sample, and it has a way to create a pin in user mode, but that method is not suitable for me. Actually, there are two user mode applications in this project to communicate with the same driver, but only one pin can be instantiated. In one applicaiton, only filter created and sent property to driver, the property is used by pin created in the second application (such as graphedit) which instantiated filter first. The problem is in the driver, I could not get the handle to the pin created by the second application. Do you have any ideas to set the property to the pin? Thank you very much. Yong