The jet crashed near the city of Rongcheng on Sunday, leaving two pilots dead, the ministry said in a statement.
The secretive People's Liberation Army rarely releases details about such accidents.
The crash occurred in the afternoon, when the pilots were in the middle of a training mission. No collateral damage on the ground was reported, according to the air force.
The PLA Air Force rushed to rescue the pilots after the crash. Condolences were offered for the two pilots, the state-run Xinhua news agency reported.
Initial photos showing the crashed aircraft began appearing on microblogs on Sunday.
China has acquired a total of 40 Su-27 UBKs from Russia since 1992. The last batch of 28 aircraft was delivered to the PLAAF in 2000 to speed up the training of pilots, Daniel Tong, founder of the Chinese Military Aviation website, told the Global Times.
The introduction of the Su-27 series fighter gave the PLAAF for the first time an admirable capability both in beyond-visual-range air combat and dogfights, he said.
Due to the lack of advanced training, Su-27UBKs have been intensively used to train third-generation fighter pilots.
China began producing the Su-27 series in 1996 and has developed at least four versions fully using domestically made parts and sub-systems.
The J-11BS double-seat fighter, which is already being delivered to the PLA, will eventually replace the Su-27UBK, said Tong.