Baidu Inc more than doubled its quarterly profit and forecast stronger-than-expected revenue for the second quarter, betting on strong online advertising demand among China's businesses.

Baidu, which has increased its focus on e-commerce and online video, surged in dominance in China's search market after Google Inc curtailed its operations following a high-profile fallout with Beijing over censorship last year.

Hong Kong-based JPMorgan analyst Dick Wei said Baidu looked well-positioned in the social media landscape, with plans to improve its search function for microblogging.

"The Street is expecting around a 60 percent growth year-on-year, which I think is reasonable given the long-term potential for Baidu and search in China."

China, with more than 450 million users, is the world's largest Internet market, but with Internet penetration hovering around 30 percent and lack of sophisticated users outside the big cities, the potential for growth is huge.

For the first quarter, Baidu reported net income of $163.5 million, or 47 cents per American Depository Share, and its first sequential decline in profit in over a year. Analysts had estimated earnings per ADS of 45 cents.

The Beijing-based company reported profit of $70.4 million, or $2.10 per share, a year ago, before a 10-for-1 stock split.

Shares of Baidu, which have surged more than 50 percent so far this year, slipped to $150.65 in after-hours trade after closing Wednesday's regular session at $151.11.

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Baidu's Chief Financial Officer Jennifer Li said the company would continue to support long-term growth by focusing significant investment on research and development, marketing and network infrastructure, among other things, in the next few quarters.

Baidu expects second-quarter revenue of $493.3 million to $503.9 million, above analysts' forecasts of $484.2 million, according to Thomson Reuters I/B/E/S.

Robin Li, Baidu's chief executive officer, however said the company's growth rates would likely slow compared to last year, when it was boosted by its fledgling keyword advertising system, Phoenix Nest.

"This year, I think it would be a more normal sequential growth," he told analysts on a conference call.

Baidu holds a 75 percent market share in China by revenue, according to Analysys International.

But analysts see an increasingly competitive landscape in China's search market in the next few years, as competitors such as Sohu.com , Alibaba Group and Tencent Holdings wrestle for market share.

Baidu, whose named is taken from an ancient Song Dynasty poem, has been venturing out of its core search business into e-commerce, online video and social networking as competition in search heats up.

Baidu's total revenue for the first quarter was $372 million, above its own forecast of $360.6 million to $371.2 million and up roughly 88 percent from a year ago. Analysts estimates called for revenue of $367.3 million.