The ruling Communist party's disciplinary body said it targeted 26 SOEs in a round of investigations that began late February, the state-run China Daily reported.
"Around 20 senior managers from these SOEs have been held on corruption charges," the paper said.
The move comes as China attempts to push wide-ranging reform of its sprawling SOEs, seen by many as an inefficient drag on economic growth.
It quoted Li Wusi, the chief inspector into China National Petroleum Corp, as saying that corruption in some areas was "rampant".
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"Problems such as using public funds to pay for personal tourism, shopping and allowances are rampant."
The report highlighted corruption in the oil and refining sector, adding that five senior managers from China's three biggest oil enterprises were being held.
Earlier this month, a court jailed China's former security chief Zhou Yongkang for life on corruption charges, the highest-ranking former official to be sentenced in decades.
Zhou was also a former oil official and remained a powerful figure in the country's energy sector.
But critics say that lack of systemic reforms, such as separating the judiciary from government control or allowing media to report freely on graft, mean the drive is little more than an excuse for political infighting.
The Central Commission for Discipline Inspection said on Wednesday that it was probing Long Zenglai, the former CEO of China Investment Securities, according to the China Daily.
The inspection found that Long spent 400,000 yuan (USD 64,400) of public money on "extravagant meals" and nearly 35,000 yuan on golf from January 2013 to May 2015, the paper said.