An entertaining game ended goalless at Selhurst as Palace extended their unbeaten run to seven and made it five clean sheets in a row.
It was a packed crowd that welcomed Reading as Palace's Family Day saw the meeting of two of the Championship's form teams.
The Royals tested Palace keeper Julian Speroni immediately with Jem Karacan and Kaspars Gorkss firing goal-wards but the Argentine dealt with both efforts well. For the home side Sean Scannell in particular looked good early on and Jonny Williams almost capitalised on a Glenn Murray flick-on.
Palace just about had the better of the opening half an hour with Scannell, Williams and Zaha all impressing but failed to test Adam Federici in the visitors' goal. For Reading it was Karacan again who came closest in the opening half with a ferocious strike that Speroni did well to turn round the post.
The Eagles then put together the best move of the game but were denied by the off-side flag. Williams' clever clipped through ball found Murray's run and the target-man finished beautifully only for the goal to be ruled out.
Both teams huffed and puffed in the final ten minutes of the half but defences remained on top until half-time.
The visitors started the second half much the better though and Hal Robson-Kanu should have scored from Jobi McAnuff's cross but headed badly wide from eight yards. Down the other end Williams quick-feet won a free-kick on the edge of the box but Mile Jedinak's free-kick went straight into the wall.
It was the Australian though who came closest next, heading Scannell's free-kick goalwards but seeing his countryman Federici pull off an excellent save as he tipped the effort over. Palace were on top now and Brian McDermott reacted by sending on Jimmy Kebe and Noel Hunt for Robson-Kanu and Simon Church.
His changes seemed to spark the Royals into life and Adam Le Fondre almost immediately hit the cross bar with a header from no more than six yards. With the visitors now firmly on top Dougie Freedman rang changes of his own, Williams and Scannell making way for Darren Ambrose and Jonathan Parr.
Parr almost made an impact immediately, getting into the position to reach Murray's flick-on but hammering a volleyed effort just wide and into the hoardings. Ambrose too made an impact and his corner with five minutes remaining was headed goalwards by Jedinak, and off the line by Karacan. Parr again threatened with the crowd screaming for a penalty, but Federici's outstretched hand did get a touch on the ball.
Reading then almost stole all three points as Kaspars Gorkks stole onto a corner in the last minute and headed home but the goal was ruled out, seemingly for a foul on Speroni, and the game ended level.
Crystal Palace: 1. Julian Speroni, 2. Nathaniel Clyne, 3. David Wright, 5. Paddy McCarthy, 6. Anthony Gardner, 11. Sean Scannell (7. Darren Ambrose '77), 15. Mile Jedinak, 16. Wilfried Zaha, 17. Glenn Murray, 20. Jonathan Williams (4. Jonathan Parr '81), 21. Dean Moxey
Subs Not Used: 34. Lewis Price, 8. Kagisho Dikgacoi, 19. Jermaine Easter
Reading: 1. Adam Federici, 4. Jem Karcan, 5. Alex Pearce, 8. Mikele Leigertwood, 9. Adam Le Fondre, 11. Jobi McAnuff, 16. Joseph Mills, 17. Kaspars Gorkss, 18. Simon Church (10. Noel Hunt '72), 19. Hal Robson-Kanu (14. Jimmy Kebe '72) 24. Shaun Cummings
Subs Not Used: 12. Alex McCarthy, 22. Mathieu Manset, 23. Ian Harte
Bookings: Mills, McAnuff, Robson-Kanu, Karacan
Att: 21,002 (Away: 1,321)