Jason Tovey booted the hosts into an early lead but Ulster quickly took control of the encounter with tries from Michael Allen and Nick Williams.
The Blues were dealt a major blow with the loss of Tovey with a suspected broken leg just minutes before the break.
But Ulster, playing for the first time since the tragic loss of Nevin Spence, who died in a farming accident alongside his father Noel and brother Graham, compounded the hosts’ woes.
Tommy Bowe, making his first competitive appearance since returning to the province grabbed a brace and he was joined on the scoreboard by Jared Payne, Williams and Andrew Trimble.
Tovey booted the Blues into an early 6-0 lead at Cardiff Arms Park before Paddy Jackson hit-back.
But with a dominant scrum causing Cardiff problems Ulster began to establish a foothold and they soon took the lead.
Following several resets at a five-metre scrum the ball was spread to Allen, who twisted over. Jackson coolly slotted the extras but Cardiff responded with the boot of Tovey to regain the lead.
However, it did not last long with Paul Marshall’s superb blindside break making the inroads for Williams’ try. Jackson was again on target and Ulster held off a fight-back to enter the break leading 17-9.
Gareth Davies, on for Tovey, cut the deficit within minutes of the restart. But Ulster struck with Bowe’s first try back in Ulster colours. A sublime slip pass from Jackson created the opening and the Irish flyer skipped past James to score.
And they quickly put the result beyond doubt with two tries in as many minutes. Jared Payne grabbed the first after collecting his own chip to race clear and wrap up the bonus-point. Then Bowe continued the rout with his second.
Cardiff nicked a consolation try when Harry Robinson latched on to James’ flick pass. But Ulster rounded off their comprehensive victory with further tries for Williams and Trimble.
