Many parents were picking up their children when the blast took place, according to the official Xinhua news agency.
Videos purportedly from the scene and posted on social media showed children and adults lying on the ground. Some were bleeding.
The blast struck at 4:50 p.m. local time (4:50 a.m. ET) Thursday in the city of Fengxian in Jiangsu province.
A cellphone camera video posted on the website of the official People's Daily newspaper showed more than a dozen people lying motionless in front of the kindergarten's steel sliding gate, with clothing, shoes and other items strewn on the ground beside pools of blood.
State-run CCTV put the death toll at seven, adding that nine of the 59 wounded were "severely injured."
It wasn't clear whether the blast was an accident or was deliberately set. The Xiandaikuaibao newspaper cited an unidentified witness as saying the explosion appeared to have been linked to a bottle of cooking gas.
Blasts and other accidents are common in China, because of patchy enforcement of safety rules.
Kindergartens in China have been targeted before in apparent revenge attacks carried out by people bearing grudges against their neighbors and society.
That has prompted a tightening of security around many schools, with the posting of guards equipped with truncheons and the installation of gates and other barriers.
China maintains tight control over firearms and most attacks are carried out using knives, axes or homemade explosives.
China kindergarten explosion: 7 killed, 59 wounded by blast
16 June 2017
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At least seven people died and 59 others were injured when an explosion struck the entrance of a kindergarten in China, state media reported Thursday.
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