Baidu didn't elaborate in a brief statement Monday.
"We appreciate all that Yinan has contributed to Baidu and we wish him every success in his future endeavors," said Robin Li, Baidu's chairman and CEO, in the press release.
The Wall Street Journal reports the resignation isn't related to Google's (GOOG - Get Report) statement last week that it was considering withdrawing from the Chinese market. In fact, many analysts believe Baidu would be the main beneficiary if Google was to exit China.Instead it has to do with the rollout of a new advertising tool that Baidu has struggled with, the newspaper reports. The chief technology officer's resignation follows Chief Operating Officer Peng Ye's resignation less than two weeks ago, also for personal reasons, Baidu said. -- Reported by Joseph Woelfel in New York. Follow TheStreet.com on Twitter and become a fan on Facebook.