Top-ranked James Willstrop, bidding for his first world crown, was undone by El Shorbagy 11-9, 9-11, 14-12, 4-11, 11-8, and defending champion Nick Matthew was sent packing by Ashour 11-9, 11-5, 9-11, 11-8 in the other semifinal.
Ashour ensured he will regain the No. 1 ranking for the first time since 2010.
He could also win his first world title since 2008 on Saturday when he faces El Shorbagy, the youngest player in the top 25 at 21, and playing his first world final.
El Shorbagy, came from 8-7 down to take the fifth and last game after 112 minutes, for only his second win over Willstrop in nine matches. El Shorbagy then ran into the arms of his parents and brother.