First of all, I am sorry about my English skill.
I have a topology and I want to integrate the Snort with pfSense.
Can pfSense auto add firewall rules when Snort alert?
Does pfSense have function to do this action?
Snort will automatically block the ip address of the offender, for the time period that you select, thus adding the firewall rule that blocked the offender is not really necessary as they get blocked automatically. The Snort rules define what traffic is blocked and you determine what rule set(s) you would like it to filter traffic with.
See screen shots for a little more information.