The new race, set up after the successful Tour de France Grand Depart in Yorkshire last July, started in Bridlington and ended in Scarborough.
"Yorkshire did us proud," said race organiser Gary Verity. "They turned out in their tens of thousands.
"The police estimate over a quarter of a million people over the whole day."
Mr Verity, chief executive of tourism body Welcome to Yorkshire, said: "The only race that gets crowds like this is the Tour de France which is a testament to the people of Yorkshire - again they nailed it."
The benefit to Yorkshire's economy from hosting the Tour de France last year was estimated at about Â£100m.
This year, Mr Verity is predicting something in the region of Â£30m-Â£40m will be generated for the regional economy by the Tour de Yorkshire.
"We are organising a race because there is a big demand for it," he said.
"In 10 years' time, maybe people will love it less, maybe they will love it more. We would love to be sat here in 50 years' time discussing the 50th edition.
"From the point of view of Yorkshire and growing the economy here and the culture of cycling, this has to be a successful event."
Stage Two of the three-day event saw the riders tackle a 174km route from Selby to York on Saturday, with the event set to finish on Sunday after a 167km ride from Wakefield to Leeds via Barnsley.
More than 250,000 people turned out to watch the first day of the inaugural Tour de Yorkshire cycle race on Friday, organisers say.