During a half-year investigation, Chinese police said they had uncovered more than 700 middlemen through which the pharmaceutical giant allegedly funnelled money to health officials and doctors in order to prescribe GSK drugs.
The company also allegedly committed some unspecified "tax-related crimes".
"This company has been investigated for bribery allegations in many countries. From our investigation, bribery is part of the strategy of this company. This is why they have bribery activities in China," said Gao Feng, the head of the economic crimes investigation unit at the Ministry of Public Security.
Four senior GSK executives, all Chinese, are now in detention, Mr Gao said.
According to the Beijing News, the detainees are Zhao Hongyan, 41, GSK's legal counsel and head of compliance, Liang Hong, 49, a vice president in charge of operations, Huang Hong, 45, a general manager in charge of commercial development and Zhang Guowei, 50, the company's human resources director.
Mark Reilly, the English head of GSK's China business, departed China on June 27 and has not returned, he added.