The visitors were 2-0 up after 11 minutes thanks to goals from Guillermo Franco and Jack Collison but Hull came back and were amazingly 3-2 up at half-time thanks to a deflected free-kick and penalty from Jimmy Bullard and a Kamil Zayatte strike.
However, the home side were reduced to ten men in the second half when Bernard Mendy received his marching orders. Then West Ham grabbed the equaliser minutes later through Manuel Da Costa.
The visitors broke the deadlock on five minutes as a Junior Stanislas corner found the head of Franco, who made no mistake from close range to register his second goal of the season.
Gianfranco Zola's men were then 2-0 up on 11 minutes as Franco turned provider with a curling cross from the right onto the head of Collison, whose looping effort from 12 yards dipped over the stranded Matt Duke and into the back of the net.
Bullard got his Hull side back into the game on 27 minutes as the ex-West Ham trainee fired in a right-footed free-kick from 18 yards which found the top right-hand corner of the net via deflections off the leg of Scott Parker and the head of Carlton Cole.
The home side were level on 44 minutes when Stephen Hunt's free-kick found an unmarked Zayatte who fired the ball home from close range to grab his second goal of the season.
Then, to cap a frantic first half, Phil Brown's men were awarded a penalty in first-half stoppage time when Julien Faubert was adjudged to have pushed Craig Fagan just inside the box. Bullard then stepped up to slam the ball home and send his side into a 3-2 lead at half time.
Hull were down to ten men on 53 minutes when Mendy was adjudged to have been the last man after scything down Parker on the edge of the box, leaving referee Mark Clattenburg no choice but to send off the French right-back.
West Ham grabbed the equaliser on 69 minutes as the Hull defence failed to clear a Stanislas corner allowing Da Costa to nip in and thump the ball into the back of the net from eight yards.
Collison came close with a header late on for the Hammers but Duke was on hand to make a great save and smother the danger.